Porous materials, methods of making and uses

ABSTRACT

The present specification discloses porous materials, methods of forming such porous materials, materials and devices comprising such porous materials, and methods of making such materials and devices.

This application is a continuation of U.S. patent application Ser. No.13/247,835, filed Sep. 28, 2011, which claims priority to U.S. PatentApplication Ser. No. 61/387,074, filed Sep. 28, 2010, the entiredisclosure of which are incorporated herein by this reference.

Polyurethanes are a class of compounds formed by reacting a polyol witha diisocyanate or a polymeric isocyanate in the presence of suitablecatalysts and additives. The structural geometry enables this highlydurable material to be produced with varying density (such as, e.g., 6kg/m3 to about 1,200 kg/m3) and flexible (flexible, semi-rigid andrigid), making polyurethane foam an ideal candidate for a wide varietyof uses in both industrial and household applications. For example,flexible polyurethane foam may be produced in a variety of shapes andfirmnesses useful as cushion underlay for carpets; as upholstery paddingfor furniture and vehicle interior components like seats, headrests,armrests, roof liners, dashboards, and instrument panels; as materialfor pillows, mattress bedding, toppers, and cores; as sponges; as mid-and outsoles of footwear; as vehicle fascia and other exterior parts; asfabric coatings as synthetic fibers; as packaging material; as integralskin form for vehicle interiors; and as sound-deadening material. Asanother example, polyurethane foam may be produced as a rigid and lightweight material useful in the manufacturing of insulating material suchas, e.g., panel or spray insulation in buildings, water heaters,refrigerated transport, and commercial and residential refrigeration.Rigid polyurethane foams are also used in the manufacture of structuralcomponents, simulated wood, and flotation devices like boats, surfboardsand life preservers. As yet another example, polyurethane foam may beproduced having a wide variety of pore sizes useful in the manufactureof cleaning material such as, e.g., wipes, swabs, and abrasives; andfiltration materials for air and/or liquid filtration.

Despite its immense versatility, there are several disadvantagesassociated with polyurethane foams that limit the scope of itsapplicability and usefulness. For example, polyurethane is unstable inthe presence of chemicals (like acids, bases, and metal salts),oxidation, UV light, thermal, radiation, and. In addition, depending onits formulation, polyurethane absorbs a large range of organic solvents(like NMP, DMSO, DCM, xylene, hexane, dioxane, and acetone) causingdeformation of its structure due to swelling. Further, degradation ofpolyurethane produces toxic byproducts that are harmful to organisms andthe environment.

All of these disadvantages have an impact on polyurethane's performancerange, for example, its use as filtration materials in applicationsinvolving solvents, acids, bases, and/or metal salts; its use asinsulation materials in applications that also comprise solvents, acids,and/or bases; its use as materials in environmentally harsh applicationswhere there is exposure to oxidation, metal salts, high UV, and/orradiation; its use as a biomedical material, like a component of amedical device, scaffolds (templates) for tissueengineering/regeneration, wound dressings, drug release matrixes,membranes for separations and filtration, sterile filters, artificialkidneys, absorbents, hemostatic devices, where biocompatibility andresistance to biodegradation are important.

SUMMARY

The present specification discloses novel porous materials. In oneaspect of the invention, such materials may have a structural geometrysubstantially similar to polyurethane-based materials but with improvedor different acid stability/resistance, base stability/resistance,chemical stability/resistance, thermal stability/resistance, oxidationstability/resistance, UV light stability/resistance, biocompatibility,biodegradation resistance, increased gas permeability, and/or increasedrange of mechanical properties, relative to polyurethane-basedmaterials. As such, the disclosed porous materials are not only usefulin all applications currently fulfilled by polyurethane-based materials,but also in many additional applications not suitable forpolyurethane-based materials. For example, the porous materialsdisclosed herein can be used in a filter for separating or cleaningmaterial present in a chemically aggressive environment, as a componentof a medical device where biocompatibility and/or biostability aredesired, as a material, or component thereof, exposed to chemical,oxidative, UV light, thermal and/or radiation environment that woulddestabilize and/or degrade a polyurethane-based material.

Thus, aspects of the present specification disclose a porous materialcomprising a matrix defining an array of interconnected pores. Thematrix material can be a thermoset polymer, a thermoplastic polymer, anelastomer or a thermoplastic elastomer.

Other aspects of the present specification disclose a method of forminga porous material, the method comprising the steps of: a) coatingporogens with a matrix material base to form a matrix material-coatedporogen mixture; b) treating the matrix material-coated porogen mixtureto form a porogen scaffold comprising fused porogens and cured or hardenmatrix material; and c) removing the porogen scaffold, wherein porogenscaffold removal results in a porous material, the porous materialcomprising a matrix defining an array of interconnected pores. Thematrix material can be a thermoset polymer, a thermoplastic polymer, anelastomer or a thermoplastic elastomer.

Yet other aspects of the present specification disclose a porousmaterial comprising a matrix defining an array of interconnected pores,wherein the porous material is made by the method comprising the stepsof: a) coating porogens with a matrix material base to form a matrixmaterial-coated porogen mixture; b) treating the matrix material-coatedporogen mixture to form a porogen scaffold comprising fused porogens andcured or harden matrix material; and c) removing the porogen scaffold,wherein porogen scaffold removal results in a porous material, theporous material comprising a matrix defining an array of interconnectedpores. The matrix material can be a thermoset polymer, a thermoplasticpolymer, an elastomer or a thermoplastic elastomer.

Further aspects of the present specification disclose a method formaking a molded article or device having a porous surface, the methodcomprising the step of: a) coating a mold or mandrel with a matrixmaterial base; b) curing the matrix material base to form a base layer;c) coating the cured base layer with a matrix material base; d) coatingthe matrix material base with porogens to form a matrix material-coatedporogen mixture; e) treating the matrix material-coated porogen mixtureto form a porogen scaffold comprising fused porogens and cured matrixmaterial base; and f) removing the porogen scaffold, wherein porogenscaffold removal results in a porous material, the porous materialcomprising a matrix defining an array of interconnected pores. In thismethod steps (c) and (d) can be repeated multiple times until thedesired thickness of the matrix material layer is achieved. The matrixmaterial can be a thermoset polymer, an elastomer or a thermoplasticelastomer.

In another aspect of the invention, an article of manufacture isprovided, generally comprising a porous silicone elastomeric materialmade by the methods disclosed herein.

Porous materials of the present invention can be used in numerous andvaried applications. In the biomedical field, porous materials of theinvention can be used as a matrix for tissue engineering/regeneration,wound dressings, drug release matrices, membranes for separations andfiltration, sterile filters, artificial kidneys, absorbents, hemostaticdevices, and the like. In various industrial and household applications,porous materials of the invention can be used as insulating materials,packaging materials, impact absorbers, liquid or gas absorbents, wounddressings, personal hygiene products, such as but not limited to,cleaning and cleansing pads, wipes and swabs, deodorant, disposabletowels, dry shampoo, facial tissues, handkerchiefs, hygiene wipes, papertowels, shaving brushes, tampons, towels, underarm liners, washingmitts, and wet wipes, membranes, filters and so forth.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is scanning electron micrograph image at 50× magnification of amaterial made in accordance with a method of the present invention.

FIG. 1B is scanning electron micrograph image at 50× magnification ofanother material made in accordance with a method of the presentinvention.

DETAILED DESCRIPTION

The present specification discloses, in part, a porous material. Aporous material disclosed herein can be made from any flowable ordissolvable matrix material that can be applied using the methodsdisclosed herein. Non-limiting examples of a flowable or dissolvablematrix material include thermoset polymers, thermoplastic polymers,elastomers, thermoplastic elastomers, or combinations thereof. A matrixmaterial may comprise homopolymers or copolymers that are degradable,substantially non-degradable, or non-degradable. A matrix materialuseful in making the porous material disclosed herein may comprise blockcopolymers, random copolymers, alternating copolymers, graft copolymers,and/or mixtures thereof of thermoset polymers, thermoplastic polymers,elastomers, thermoplastic elastomers having an isotactic, syndiotacticor atactic organization. Isotactic polymers have all substituentslocated on the same side of the polymer backbone; the polymer comprises100% meso diads. Syndiotactic polymers or syntactic polymers comprisehave substituents in alternate positions along the chain; the polymercomprises 100% of racemo diads. Atactic polymers have substituentsplaced randomly along the chain; the polymer comprises between 1 and 99%meso diads. Such matrix materials include, for example carbon-basedpolymers, fluorocarbon-based polymers, and silicone-based polymers,including, without limitation, polyolefins, polyacrylates,fluoropolymers, polysiloxanes, polyesters, polyethers, polycarbonates,polyamides, polyanhydrides, polyorthoesters, polyurethanes, polyureas,polysaccharides, polyalkanes, polyalkenes, polyalkynes, nitriles, andfluorosilicones.

The present specification discloses, in part, a thermoset polymer. Asused herein, the term “thermoset” or “thermoset polymer” refers to amaterial that irreversibly hardens (i.e., sets) into a given shape,generally through a curing process. A thermoset polymer may comprisehomopolymers or copolymers that are degradable, substantiallynon-degradable, or non-degradable. A thermoset polymer useful in makingthe porous material disclosed herein may comprise block copolymers,random copolymers, alternating copolymers, graft copolymers, and/ormixtures thereof. Thermoset polymers outperform other materials (such asthermoplastics, see below) in a number of areas, including mechanicalproperties, chemical resistance, thermal stability, and overalldurability. Thermoplastics include, without limitation, thermosetelastomers including carbon-based thermoset elastomers,fluorocarbon-based thermoset elastomers and silicone-based thermosetelastomers; formaldehyde-based thermoset polymers likephenol-formaldehyde, urea-formaldehyde, melamine formaldehyde;poly(ester)-based thermoset polymers; poly(epoxide)-based thermosetpolymers; poly(imide)-based thermoset polymers; andpoly(cyanurate)-based thermoset polymers.

The present specification discloses, in part, a thermoplastic polymer.As used herein, the term “thermoplastic”, “thermoplastic polymer”, or“thermosoftening plastic” refers to a material that softens and becomesfluid when heated and which hardens or freezes to a very glassy statewhen cooled sufficiently. Thermoplastics are elastic and flexible abovea glass transition temperature Tg, the midpoint of a temperature range.Below a second, higher melting temperature, Tm, also the midpoint of arange, most thermoplastics have crystalline regions alternating withamorphous regions in which the chains approximate random coils. Theamorphous regions contribute elasticity and the crystalline regionscontribute strength and rigidity. Above Tm all crystalline structuredisappears and the chains become randomly inter dispersed. As thetemperature increases above Tm, viscosity gradually decreases withoutany distinct phase change. During processing, thermoplastic pellets areheated to a fluid state that allows the material to be injected underpressure from a heated cavity into a cool mold. As the material cools,the thermoplastic will harden in the shape of the mold. However, nocross-links are formed as with a thermoset polymer (i.e., no curing).Thermoplastic polymers differ from thermosetting polymers in that thechanges seen are purely physical and, with the reapplication of heat,wholly reversible. As such, thermoplastics can be reprocessed many timesthrough a cycle of remelting and remolding. Most thermoplastics arehigh-molecular-weight polymers whose chains associate through weak Vander Waals forces; stronger dipole-dipole interactions and hydrogenbonding; or even stacking of aromatic rings. Thermoplastics include,e.g., amorphous thermoplastics, semi-crystalline thermoplastics,crystalline thermoplastics, and elastomeric and include, withoutlimitation, poly(aryletherketone) (PAEK), poly(butylene terephthalate)(PBT), poly(butyrate), poly(ether ether ketone) (PEEK), poly(etherimide)(PEI), poly(2-hydroxyethyl methacrylate) (pHEMA), poly(isocyanurate)(PIR), poly(methyl methacrylate) (PMMA), poly(oxymethylene) (POM);poly(phenylsulfone) (PPSF), poly(styrene) (PS), poly(trimethyleneterephthalate) (PTT), poly(urea) (PU); poly(amide)-based thermoplasticslike aliphatic poly(amides), poly(phthalamides) (PPA), and aramides(aromatic poly(amides)); poly(carbonate)-based thermoplastics;poly(ester)-based thermoplastics like poly(ethylene) naphthalate (PEN),and poly(ethylene terephthalate) (PET); poly(olefin)-basedthermoplastics like poly(ethylene) (PE), poly(propylene) (PP),poly(propylene carbonate) (PPC), poly(methylpentene) (PMP), andpoly(butene-1) (PB-1); poly(stannane)-based thermoplastics;poly(sulfone)-based thermoplastics; poly(vinyl)-based thermoplasticslike poly(vinyl chloride) (PVC), poly(vinylidene fluoride) (PVDF),poly(vinyl fluoride) (PVF), poly(vinyl nitrate) (PVN), andpoly-(4-vinylphenol) (PVP); and cellulose-based thermoplastic likecellulose ester-based thermoplastics and cellulose ether-basedthermoplastics.

The present specification discloses, in part, a fluoropolymer. As usedherein, the term “fluoropolymer” refers to a fluorocarbon-based polymerwith multiple strong carbon-fluorine bonds characterized by a highresistance to solvents, acids, and bases. Fluoropolymers include,without limitation, poly(vinyl fluoride) (PVF), poly(vinylidenefluoride) (PVDF), poly(tetrafluoroethylene) (PTFE),poly(chlorotrifluoroethylene) (PCTFE), perfluoroalkoxy (PFA),fluorinated ethylene-propylene (FEP), polyethylenetetrafluoroethylene(ETFE), poly(ethylenechlorotrifluoroethylene) (ECTFE),perfluoropolyether (PFPE) and fluoroelastomers.

The present specification discloses, in part, an elastomer. As usedherein, the term “elastomer” or “elastic polymer” is synonymous with“thermoset elastomer” refers to an amorphous polymer that exists aboveits glass transition temperature (T_(g)) at ambient temperatures,thereby conferring the property of viscoelasticity so that considerablesegmental motion is possible. Elastomers include, without limitation,carbon-based elastomers, silicone-based elastomers, thermosetelastomers, and thermoplastic elastomers. As used herein, the term“ambient temperature” refers to a temperature of about 18° C. to about22° C. Elastomers, either naturally-occurring or synthetically-made,comprise monomers commonly made of carbon, hydrogen, oxygen, and/orsilicone which are linked together to form long polymer chains.Elastomers are typically covalently cross-linked to one another,although non-covalently cross-linked elastomers are known. An elastomermay comprise homopolymers or copolymers that are degradable,substantially non-degradable, or non-degradable. An elastomer useful inmaking the porous material disclosed herein may comprise blockcopolymers, random copolymers, alternating copolymers, graft copolymers,and/or mixtures thereof. Unlike other polymers classes, an elastomer canbe stretched many times its original length without breaking byreconfiguring themselves to distribute an applied stress, and thecross-linkages ensure that the elastomers will return to their originalconfiguration when the stress is removed. Elastomers can be anon-medical grade elastomer or a medical grade elastomer. Medical gradeelastomers are typically divided into three categories: non-implantable,short term implantable and long-term implantable. Exemplary elastomersinclude, without limitation, bromo isobutylene isoprene (BIIR),polybutadiene (BR), chloro isobutylene isoprene (CIIR), polychloroprene(CR), chlorosulphonated polyethylene (CSM), diphenylsiloxane (DPS),ethylene propylene (EP), ethylene propylene diene monomer (EPDM),fluorinated hydrocarbon (FKM), fluoro silicone (FVQM), hydrogenatednitrile butadiene (HNBR), polyisoprene (IR), isobutylene isoprene butyl(IIR), methyl vinyl silicone (MVQ), nitrile acrylonitrile butadiene(NBR), polyurethane (PU), styrene butadiene (SBR), styreneethylene/butylene styrene (SEBS), polydimethylsiloxane (PDMS),polysiloxane (SI), acrylonitrile butadiene carboxy monomer (XNBR), andpolyolefin elastomers like polyisobutylene (PIB), ethylene propylenerubber (EPR), ethylene propylene diene monomer (EPDM).

The present specification discloses, in part, an elastomer that is afluorocarbon-based elastomer. As used herein, the tem“fluorocarbon-based elastomer” refers to any fluorocarbon containingelastomer, such as, e.g., fluoro-elastomers (FKM), perfluoro-elastomers(FFKM) and tetrafluoro-ethylene/propylene elastomers (FEPM).

The present specification discloses, in part, an elastomer that is asilicone-based elastomer. In some embodiments, materials are providedwhich are substantially entirely silicone. As used herein, the tem“silicone-based elastomer” refers to any silicone containing elastomer,such as, e.g., methyl vinyl silicone, polydimethylsiloxane, orpolysiloxane. A silicone-based elastomer can be a high temperaturevulcanization (HTV) silicone or a room temperature vulcanization (RTV).A silicone-based elastomer can be a non-medical grade silicone-basedelastomer or a medical grade silicone-based elastomer. As used herein,the term “medical grade silicone-based elastomer” refers to asilicone-based elastomer approved by the U.S. Pharmacopeia (USP) as atleast Class V. Medical grade silicone-based elastomers are typicallydivided into three categories: non-implantable, short term implantableand long-term implantable.

Thus, in an embodiment, an elastomer is a medical grade elastomer. Inaspects of this embodiment, a medical grade elastomer is, e.g., amedical grade carbon-based elastomer, a medical grade silicone-basedelastomer, a medical grade thermoset elastomer, or a medical gradethermoplastic elastomer. In other aspects of this embodiment, anelastomer is, e.g., a medical grade, long-term implantable, carbon-basedelastomer, a medical grade, long-term implantable, silicone-basedelastomer, a medical grade, long-term implantable, thermoset elastomer,or a medical grade, long-term implantable, thermoplastic elastomer. Instill other aspects, a medical grade elastomer is, e.g., a medical gradebromo isobutylene isoprene, a medical grade polybutadiene, a medicalgrade chloro isobutylene isoprene, a medical grade polychloroprene, amedical grade chlorosulphonated polyethylene, a medical grade ethylenepropylene, a medical grade ethylene propylene diene monomer, a medicalgrade fluorinated hydrocarbon, a medical grade fluoro silicone, amedical grade hydrogenated nitrile butadiene, a medical gradepolyisoprene, a medical grade isobutylene isoprene butyl, a medicalgrade methyl vinyl silicone, a medical grade acrylonitrile butadiene, amedical grade polyurethane, a medical grade styrene butadiene, a medicalgrade styrene ethylene/butylene styrene, a medical gradepolydimethylsiloxane, a medical grade polysiloxane, or a medical gradeacrylonitrile butadiene carboxy monomer.

In another embodiment, an elastomer is a silicone-based elastomer. In anaspect of this embodiment, a silicone-based elastomer is a medical gradesilicone-based elastomer. In aspects of this embodiment, a medical gradesilicone-based elastomer is, e.g., at least a USP Class V silicone-basedelastomer, at least a USP Class VI silicone-based elastomer, or USPClass VII silicone-based elastomer. In yet other aspects, a medicalgrade silicone-based elastomer is a long-term implantable silicone-basedelastomer. In yet other aspects, a medical grade silicone-basedelastomer is, e.g., a medical grade, long-term implantable, methyl vinylsilicone, a medical grade, long-term implantable, polydimethylsiloxane,or a medical grade, long-term implantable, polysiloxane.

The present specification discloses, in part, a thermoplastic elastomer.As used herein, the term “thermoplastic elastomer” or “thermoplasticrubber” refers to a material comprising a class of copolymers or aphysical mix of polymers of a plastic and an elastomer that exhibit boththermoplastic and elastomeric properties. The principal differencebetween thermoset elastomers and thermoplastic elastomers is the type ofcrosslinking bond in their structures. In fact, crosslinking is acritical structural factor that contributes to impart high elasticproperties. The crosslink in thermoset polymers is a covalent bondcreated during the vulcanization process. On the other hand, thecrosslink in thermoplastic elastomer polymers is a weaker dipole orhydrogen bond or takes place in one of the phases of the material. Athermoplastic elastomer combines the elastomer-like properties of athermoset elastomer and the processing characteristics of athermoplastic. The TPE achieves this blend because it is composed of tworegions (or phases): soft phases (cured thermoset rubber particles)dispersed within hard phases (the thermoplastic portion). Be aware thatthe physical, chemical, and thermal limits of both phases will determinethe overall limits for the TPE. Because it is a blended material, a TPEis also considerably more expensive than a simpler thermoset material.Thermoplastic elastomers include, without limitation, styrenic blockcopolymers, elastomeric alloys, thermoplastic polyurethanes,thermoplastic polyester elastomers copolymers, polyolefin blends,thermoplastic polyester blends, and thermoplastic polyamides blends.Non-limiting examples, include, ethylene-vinyl acetate (EVA), copolymersof polypropylene and ethylene propylene diene monomer (EPDM) elastomer,copolymers of polystyrene and polybutadiene, and copolymers ofpolystyrene and polyisoprene.

Elastomers have the property of viscoelasticity. Viscoelasticity is theproperty of materials that exhibit both viscous and elasticcharacteristics when undergoing deformation. Viscous materials resistshear flow and strain linearly with time when a stress is applied.Elastic materials strain instantaneously when stretched and just asquickly return to their original state once the stress is removed.Viscoelastic materials have elements of both of these properties and, assuch, exhibit time dependent strain. A viscoelastic material has thefollowing properties: 1) hysteresis, or memory, is seen in thestress-strain curve; 2) stress relaxation occurs: step constant straincauses decreasing stress; and 3) creep occurs: step constant stresscauses increasing strain. The viscoelasticity of elastomers confer aunique set of properties involving elongation, tensile strength, shearstrength compressive modulus, and hardness that distinguish elastomersfrom other classes of polymers.

Selection of a particular matrix material is within the knowledge levelof a person of ordinary skill and will depend on the specific propertiesand characteristics desired of the porous material. For example, wherethe porous material is a component of an implantable medical device, theporous material will typically comprise a biocompatible, substantiallynon-degradable silicone-based elastomer. As another example, where theporous material is used as a component of an insulating application, theporous material will typically comprise a poly(styrene)-based lowthermal conductivity thermoset polymer. As yet another example, wherethe porous material is a component of a filtration device for chemicallyaggressive or harsh applications, the porous material will typicallycomprise a fluoropolymer thermoset. As yet another example, where theporous material is a component of a light weight armor, the porousmaterial will typically comprise a silicone-based elastomer, afluorosilicone-based elastomer, or a fluoropolymer thermoset.

The present specification discloses, in part, a porous materialcomprising a matrix defining an array of interconnected pores. As usedherein, the term “matrix defining an array of interconnected pores” or“matrix material defining an array of interconnected pores” issynonymous with “cured matrix” or “cured matrix material” and refers toa three-dimensional structural framework composed of a material, suchas, e.g. a thermoset polymer, an elastomer, or a thermoplastic elastomerin its cured state or a material, such as, e.g., a thermoplastic polymerin its harden or solid state.

A porous material comprising a matrix defining an array ofinterconnected pores may exhibit high resistance to deformation.Resistance to deformation is the ability of a material to maintain itsoriginal form after being exposed to stress, and can be calculated asthe original form of the material (L₀), divided by the form of thematerial after it is released from a stress (L_(R)), and then multipliedby 100.

In an embodiment, a porous material comprising a matrix defining anarray of interconnected pores exhibits high resistance to deformation.In aspects of this embodiment, a porous material disclosed hereinexhibits resistance to deformation of, e.g., about 100%, about 99%,about 98%, about 97%, about 96%, about 95%, about 94%, about 93%, about92%, about 91%, about 90%, about 89%, about 88%, about 87%, about 86%,or about 85%. In other aspects of this embodiment, a porous materialdisclosed herein exhibits resistance to deformation of, e.g., at least99%, at least 98%, at least 97%, at least 96%, at least 95%, at least94%, at least 93%, at least 92%, at least 91%, at least 90%, at least89%, at least 88%, at least 87%, at least 86%, or at least 85%. In yetother aspects of this embodiment, a porous material disclosed hereinexhibits resistance to deformation of, e.g., at most 99%, at most 98%,at most 97%, at most 96%, at most 95%, at most 94%, at most 93%, at most92%, at most 91%, at most 90%, at most 89%, at most 88%, at most 87%, atmost 86%, or at most 85%. In still aspects of this embodiment, a porousmaterial disclosed herein exhibits resistance to deformation of, e.g.,about 85% to about 100%, about 87% to about 100%, about 90% to about100%, about 93% to about 100%, about 95% to about 100%, or about 97% toabout 100%.

A porous material comprising a matrix defining an array ofinterconnected pores may exhibit high elastic elongation. Elongation isa type of deformation caused when a material stretches under a tensilestress. Deformation is simply a change in shape that anything undergoesunder stress. The elongation property of a material can be expressed aspercent elongation, which is calculated as the length of a materialafter it is stretched (L), divided by the original length of thematerial (L₀), and then multiplied by 100. In addition, this elasticelongation may be reversible. Reversible elongation is the ability of amaterial to return to its original length after being release for atensile stress, and can be calculated as the original length of thematerial (L₀), divided by the length of the material after it isreleased from a tensile stress (L_(R)), and then multiplied by 100.

In an embodiment, a porous material comprising a matrix defining anarray of interconnected pores exhibits high elastic elongation. Inaspects of this embodiment, a porous material disclosed herein exhibitsan elastic elongation of, e.g., about 50%, about 80%, about 100%, about200%, about 300%, about 400%, about 500%, about 600%, about 700%, about800%, about 900%, about 1000%, about 1100%, about 1200%, about 1300%,about 1400%, about 1500%, about 1600%, about 1700%, about 1800%, about1900%, or about 2000%. In other aspects of this embodiment, a porousmaterial disclosed herein exhibits an elastic elongation of, e.g., atleast 50%, at least 80%, at least 100%, at least 200%, at least 300%, atleast 400%, at least 500%, at least 600%, at least 700%, at least 800%,at least 900%, at least 1000%, at least 1100%, at least 1200%, at least1300%, at least 1400%, at least 1500%, at least 1600%, at least 1700%,at least 1800%, at least 1900%, or at least 2000%. In yet other aspectsof this embodiment, a porous material disclosed herein exhibits anelastic elongation of, e.g., at most 50%, at most 80%, at most 100%, atmost 200%, at most 300%, at most 400%, at most 500%, at most 600%, atmost 700%, at most 800%, at most 900%, at most 1000%, at most 1100%, atmost 1200%, at most 1300%, at most 1400%, at most 1500%, at most 1600%,at most 1700%, at most 1800%, at most 1900%, or at most 2000%. In stillaspects of this embodiment, a porous material disclosed herein exhibitsan elastic elongation of, e.g., about 50% to about 600%, about 50% toabout 700%, about 50% to about 800%, about 50% to about 900%, about 50%to about 1000%, about 80% to about 600%, about 80% to about 700%, about80% to about 800%, about 80% to about 900%, about 80% to about 1000%,about 100% to about 600%, about 100% to about 700%, about 100% to about800%, about 100% to about 900%, about 100% to about 1000%, about 200% toabout 600%, about 200% to about 700%, about 200% to about 800%, about200% to about 900%, or about 200% to about 1000%.

In another embodiment, a porous material comprising a matrix defining anarray of interconnected pores exhibits reversible elongation. In aspectsof this embodiment, a porous material disclosed herein exhibits areversible elastic elongation of, e.g., about 100%, about 99%, about98%, about 97%, about 96%, about 95%, about 94%, about 93%, about 92%,about 91%, about 90%, about 89%, about 88%, about 87%, about 86%, orabout 85%. In other aspects of this embodiment, a porous materialdisclosed herein exhibits a reversible elastic elongation of, e.g., atleast 99%, at least 98%, at least 97%, at least 96%, at least 95%, atleast 94%, at least 93%, at least 92%, at least 91%, at least 90%, atleast 89%, at least 88%, at least 87%, at least 86%, or at least 85%. Inyet other aspects of this embodiment, a porous material disclosed hereinexhibits a reversible elastic elongation of, e.g., at most 99%, at most98%, at most 97%, at most 96%, at most 95%, at most 94%, at most 93%, atmost 92%, at most 91%, at most 90%, at most 89%, at most 88%, at most87%, at most 86%, or at most 85%. In still aspects of this embodiment, aporous material disclosed herein exhibits a reversible elasticelongation of, e.g., about 85% to about 100%, about 87% to about 100%,about 90% to about 100%, about 93% to about 100%, about 95% to about100%, or about 97% to about 100%.

A porous material comprising a matrix defining an array ofinterconnected pores may exhibit low elastic modulus. Elastic modulus,or modulus of elasticity, refers to the ability of a material to resistsdeformation, or, conversely, an object's tendency to be non-permanentlydeformed when a force is applied to it. The elastic modulus of an objectis defined as the slope of its stress-strain curve in the elasticdeformation region: λ=stress/strain, where λ is the elastic modulus inPascal's; stress is the force causing the deformation divided by thearea to which the force is applied; and strain is the ratio of thechange caused by the stress to the original state of the object.Specifying how stresses are to be measured, including directions, allowsfor many types of elastic moduli to be defined. The three primaryelastic moduli are tensile modulus, shear modulus, and bulk modulus.

Tensile modulus (E) or Young's modulus is an objects response to linearstrain, or the tendency of an object to deform along an axis whenopposing forces are applied along that axis. It is defined as the ratioof tensile stress to tensile strain. It is often referred to simply asthe elastic modulus. The shear modulus or modulus of rigidity refers toan object's tendency to shear (the deformation of shape at constantvolume) when acted upon by opposing forces. It is defined as shearstress over shear strain. The shear modulus is part of the derivation ofviscosity. The shear modulus is concerned with the deformation of asolid when it experiences a force parallel to one of its surfaces whileits opposite face experiences an opposing force (such as friction). Thebulk modulus (K) describes volumetric elasticity or an object'sresistance to uniform compression, and is the tendency of an object todeform in all directions when uniformly loaded in all directions. It isdefined as volumetric stress over volumetric strain, and is the inverseof compressibility. The bulk modulus is an extension of Young's modulusto three dimensions.

In another embodiment, a porous material comprising a matrix defining anarray of interconnected pores exhibits low tensile modulus. In aspectsof this embodiment, a porous material disclosed herein exhibits atensile modulus of, e.g., about 0.01 MPa, about 0.02 MPa, about 0.03MPa, about 0.04 MPa, about 0.05 MPa, about 0.06 MPa, about 0.07 MPa,about 0.08 MPa, about 0.09 MPa, about 0.1 MPa, about 0.15 MPa, about 0.2MPa, about 0.25 MPa, about 0.3 MPa, about 0.35 MPa, about 0.4 MPa, about0.45 MPa, about 0.5 MPa, about 0.55 MPa, about 0.6 MPa, about 0.65 MPa,or about 0.7 MPa. In other aspects of this embodiment, a porous materialdisclosed herein exhibits a tensile modulus of, e.g., at most 0.01 MPa,at most 0.02 MPa, at most 0.03 MPa, at most 0.04 MPa, at most 0.05 MPa,at most 0.06 MPa, at most 0.07 MPa, at most 0.08 MPa, at most 0.09 MPa,at most 0.1 MPa, at most 0.15 MPa, at most 0.2 MPa, at most 0.25 MPa, atmost 0.3 MPa, at most 0.35 MPa, at most 0.4 MPa, at most 0.45 MPa, atmost 0.5 MPa, at most 0.55 MPa, at most 0.6 MPa, at most 0.65 MPa, or atmost 0.7 MPa. In yet other aspects of this embodiment, a porous materialdisclosed herein exhibits a tensile modulus of, e.g., about 0.01 MPa toabout 0.1 MPa, about 0.01 MPa to about 0.2 MPa, about 0.01 MPa to about0.3 MPa, about 0.01 MPa to about 0.4 MPa, about 0.01 MPa to about 0.5MPa, about 0.01 MPa to about 0.6 MPa, or about 0.01 MPa to about 0.7MPa.

In another embodiment, a porous material comprising a matrix defining anarray of interconnected pores exhibits low shear modulus. In aspects ofthis embodiment, a porous material disclosed herein exhibits a shearmodulus of, e.g., about 0.1 MPa, about 0.2 MPa, about 0.3 MPa, about 0.4MPa, about 0.5 MPa, about 0.6 MPa, about 0.7 MPa, about 0.8 MPa, about0.9 MPa, about 1 MPa, about 1.5 MPa, about 2 MPa, about 2.5 MPa, orabout 3 MPa. In other aspects of this embodiment, a porous materialdisclosed herein exhibits a shear modulus of, e.g., at most 0.1 MPa, atmost 0.2 MPa, at most 0.3 MPa, at most 0.4 MPa, at most 0.5 MPa, at most0.6 MPa, at most 0.7 MPa, at most 0.8 MPa, at most 0.9 MPa, at most 1MPa, at most 1.5 MPa, at most 2 MPa, at most 2.5 MPa, or at most 3 MPa.In yet other aspects of this embodiment, a porous material disclosedherein exhibits a shear modulus of, e.g., about 0.1 MPa to about 1 MPa,about 0.1 MPa to about 1.5 MPa, about 0.1 MPa to about 2 MPa, about 0.1MPa to about 2.5 MPa, or about 0.1 MPa to about 3 MPa.

In another embodiment, a porous material comprising a matrix defining anarray of interconnected pores exhibits low bulk modulus. In aspects ofthis embodiment, a porous material disclosed herein exhibits a bulkmodulus of, e.g., about 0.5 GPa, about 0.6 GPa, about 0.7 GPa, about 0.8GPa, about 0.9 GPa, about 1 GPa, about 1.5 GPa, about 2 GPa, about 2.5GPa, about 3 GPa, about 3.5 GPa, about 4 GPa, about 4.5 GPa, or about 5GPa. In other aspects of this embodiment, a porous material disclosedherein exhibits a bulk modulus of, e.g., at most 0.5 GPa, at most 0.6GPa, at most 0.7 GPa, at most 0.8 GPa, at most 0.9 GPa, at most 1 GPa,at most 1.5 GPa, at most 2 GPa, at most 2.5 GPa, at most 3 GPa, at most3.5 GPa, at most 4 GPa, at most 4.5 GPa, or at most 5 GPa. In yet otheraspects of this embodiment, a porous material disclosed herein exhibitsa bulk modulus of, e.g., about 0.5 GPa to about 5 GPa, about 0.5 GPa toabout 1 GPa, or about 1 GPa to about 5 GPa.

A porous material comprising a matrix material defining an array ofinterconnected pores may exhibit high tensile strength relative to otherpolymer classes. Other polymer classes include any other polymer notclassified as a matrix material. Tensile strength has three differentdefinitional points of stress maxima. Yield strength refers to thestress at which material strain changes from elastic deformation toplastic deformation, causing it to deform permanently. Ultimate strengthrefers to the maximum stress a material can withstand when subjected totension, compression or shearing. It is the maximum stress on thestress-strain curve. Breaking strength refers to the stress coordinateon the stress-strain curve at the point of rupture, or when the materialpulls apart.

In another embodiment, a porous material comprising a matrix defining anarray of interconnected pores exhibits high yield strength relative toother polymer classes. In aspects of this embodiment, a porous materialdisclosed herein exhibits a yield strength of, e.g., about 1 MPa, about5 MPa, about 10 MPa, about 20 MPa, about 30 MPa, about 40 MPa, about 50MPa, about 60 MPa, about 70 MPa, about 80 MPa, about 90 MPa, about 100MPa, about 200 MPa, about 300 MPa, about 400 MPa, about 500 MPa, about600 MPa, about 700 MPa, about 800 MPa, about 900 MPa, about 1000 MPa,about 1500 MPa, or about 2000 MPa. In other aspects of this embodiment,a porous material disclosed herein exhibits a yield strength of, e.g.,at least 1 MPa, at least 5 MPa, at least 10 MPa, at least 20 MPa, atleast 30 MPa, at least 40 MPa, at least 50 MPa, at least 60 MPa, atleast 70 MPa, at least 80 MPa, at least 90 MPa, at least 100 MPa, atleast 200 MPa, at least 300 MPa, at least 400 MPa, at least 500 MPa, atleast 600 MPa, at least 700 MPa, at least 800 MPa, at least 900 MPa, atleast 1000 MPa, at least 1500 MPa, or at least 2000 MPa. In yet otheraspects of this embodiment, a porous material disclosed herein exhibitsa yield strength of, e.g., at most 1 MPa, at most 5 MPa, at most 10 MPa,at most 20 MPa, at most 30 MPa, at most 40 MPa, at most 50 MPa, at most60 MPa, at most 70 MPa, at most 80 MPa, at most 90 MPa, at most 100 MPa,at most 200 MPa, at most 300 MPa, at most 400 MPa, at most 500 MPa, atmost 600 MPa, at most 700 MPa, at most 800 MPa, at most 900 MPa, at most1000 MPa, at most 1500 MPa, or at most 2000 MPa. In still other aspectsof this embodiment, a porous material disclosed herein exhibits a yieldstrength of, e.g., about 1 MPa to about 50 MPa, about 1 MPa to about 60MPa, about 1 MPa to about 70 MPa, about 1 MPa to about 80 MPa, about 1MPa to about 90 MPa, about 1 MPa to about 100 MPa, about 10 MPa to about50 MPa, about 10 MPa to about 60 MPa, about 10 MPa to about 70 MPa,about 10 MPa to about 80 MPa, about 10 MPa to about 90 MPa, about 10 MPato about 100 MPa, about 100 MPa to about 500 MPA, about 300 MPa to about500 MPA, about 300 MPa to about 1000 MPa, about 500 MPa to about 1000MPa, about 700 MPa to about 1000 MPa, about 700 MPa to about 1500 MPa,about 1000 MPa to about 1500 MPa, or about 1200 MPa to about 1500 MPa.

In another embodiment, a porous material comprising a matrix defining anarray of interconnected pores exhibits high ultimate strength relativeto other polymer classes. In aspects of this embodiment, a porousmaterial disclosed herein exhibits an ultimate strength of, e.g., about1 MPa, about 5 MPa, about 10 MPa, about 20 MPa, about 30 MPa, about 40MPa, about 50 MPa, about 60 MPa, about 70 MPa, about 80 MPa, about 90MPa, about 100 MPa, about 200 MPa, about 300 MPa, about 400 MPa, about500 MPa, about 600 MPa, about 700 MPa, about 800 MPa, about 900 MPa,about 1000 MPa, about 1500 MPa, or about 2000 MPa. In other aspects ofthis embodiment, a porous material disclosed herein exhibits an ultimatestrength of, e.g., at least 1 MPa, at least 5 MPa, at least 10 MPa, atleast 20 MPa, at least 30 MPa, at least 40 MPa, at least 50 MPa, atleast 60 MPa, at least 70 MPa, at least 80 MPa, at least 90 MPa, atleast 100 MPa, at least 200 MPa, at least 300 MPa, at least 400 MPa, atleast 500 MPa, at least 600 MPa, at least 700 MPa, at least 800 MPa, atleast 900 MPa, at least 1000 MPa, at least 1500 MPa, or at least 2000MPa. In yet other aspects of this embodiment, a porous materialdisclosed herein exhibits an ultimate strength of, e.g., at most 1 MPa,at most 5 MPa, at most 10 MPa, at most 20 MPa, at most 30 MPa, at most40 MPa, at most 50 MPa, at most 60 MPa, at most 70 MPa, at most 80 MPa,at most 90 MPa, at most 100 MPa, at most 200 MPa, at most 300 MPa, atmost 400 MPa, at most 500 MPa, at most 600 MPa, at most 700 MPa, at most800 MPa, at most 900 MPa, at most 1000 MPa, at most 1500 MPa, or at most2000 MPa. In still other aspects of this embodiment, a porous materialdisclosed herein exhibits an ultimate strength of, e.g., about 1 MPa toabout 50 MPa, about 1 MPa to about 60 MPa, about 1 MPa to about 70 MPa,about 1 MPa to about 80 MPa, about 1 MPa to about 90 MPa, about 1 MPa toabout 100 MPa, about 10 MPa to about 50 MPa, about 10 MPa to about 60MPa, about 10 MPa to about 70 MPa, about 10 MPa to about 80 MPa, about10 MPa to about 90 MPa, about 10 MPa to about 100 MPa, about 100 MPa toabout 500 MPA, about 300 MPa to about 500 MPA, about 300 MPa to about1000 MPa, about 500 MPa to about 1000 MPa, about 700 MPa to about 1000MPa, about 700 MPa to about 1500 MPa, about 1000 MPa to about 1500 MPa,or about 1200 MPa to about 1500 MPa.

In another embodiment, a porous material comprising a matrix defining anarray of interconnected pores exhibits high breaking strength relativeto other polymer classes. In aspects of this embodiment, a porousmaterial disclosed herein exhibits a breaking strength of, e.g., about 1MPa, about 5 MPa, about 10 MPa, about 20 MPa, about 30 MPa, about 40MPa, about 50 MPa, about 60 MPa, about 70 MPa, about 80 MPa, about 90MPa, about 100 MPa, about 200 MPa, about 300 MPa, about 400 MPa, about500 MPa, about 600 MPa, about 700 MPa, about 800 MPa, about 900 MPa,about 1000 MPa, about 1500 MPa, or about 2000 MPa. In other aspects ofthis embodiment, a porous material disclosed herein exhibits a breakingstrength of, e.g., at least 1 MPa, at least 5 MPa, at least 10 MPa, atleast 20 MPa, at least 30 MPa, at least 40 MPa, at least 50 MPa, atleast 60 MPa, at least 70 MPa, at least 80 MPa, at least 90 MPa, atleast 100 MPa, at least 200 MPa, at least 300 MPa, at least 400 MPa, atleast 500 MPa, at least 600 MPa, at least 700 MPa, at least 800 MPa, atleast 900 MPa, at least 1000 MPa, at least 1500 MPa, or at least 2000MPa. In yet other aspects of this embodiment, a porous materialdisclosed herein exhibits a breaking strength of, e.g., at most 1 MPa,at most 5 MPa, at most 10 MPa, at most 20 MPa, at most 30 MPa, at most40 MPa, at most 50 MPa, at most 60 MPa, at most 70 MPa, at most 80 MPa,at most 90 MPa, at most 100 MPa, at most 200 MPa, at most 300 MPa, atmost 400 MPa, at most 500 MPa, at most 600 MPa, at most 700 MPa, at most800 MPa, at most 900 MPa, at most 1000 MPa, at most 1500 MPa, or at most2000 MPa. In still other aspects of this embodiment, a porous materialdisclosed herein exhibits a breaking strength of, e.g., about 1 MPa toabout 50 MPa, about 1 MPa to about 60 MPa, about 1 MPa to about 70 MPa,about 1 MPa to about 80 MPa, about 1 MPa to about 90 MPa, about 1 MPa toabout 100 MPa, about 10 MPa to about 50 MPa, about 10 MPa to about 60MPa, about 10 MPa to about 70 MPa, about 10 MPa to about 80 MPa, about10 MPa to about 90 MPa, about 10 MPa to about 100 MPa, about 100 MPa toabout 500 MPA, about 300 MPa to about 500 MPA, about 300 MPa to about1000 MPa, about 500 MPa to about 1000 MPa, about 700 MPa to about 1000MPa, about 700 MPa to about 1500 MPa, about 1000 MPa to about 1500 MPa,or about 1200 MPa to about 1500 MPa.

A porous material comprising a matrix defining an array ofinterconnected pores may exhibit low flexural strength relative to otherpolymer classes. Flexural strength, also known as bend strength ormodulus of rupture, refers to an object's ability to resist deformationunder load and represents the highest stress experienced within theobject at its moment of rupture. It is measured in terms of stress.

In an embodiment, a porous material comprising a matrix defining anarray of interconnected pores exhibits low flexural strength relative toother polymer classes. In aspects of this embodiment, a porous materialdisclosed herein exhibits a flexural strength of, e.g., about 1 MPa,about 5 MPa, about 10 MPa, about 20 MPa, about 30 MPa, about 40 MPa,about 50 MPa, about 60 MPa, about 70 MPa, about 80 MPa, about 90 MPa,about 100 MPa, about 200 MPa, about 300 MPa, about 400 MPa, about 500MPa, about 600 MPa, about 700 MPa, about 800 MPa, about 900 MPa, about1000 MPa, about 1500 MPa, or about 2000 MPa. In other aspects of thisembodiment, a porous material disclosed herein exhibits a flexuralstrength of, e.g., at least 1 MPa, at least 5 MPa, at least 10 MPa, atleast 20 MPa, at least 30 MPa, at least 40 MPa, at least 50 MPa, atleast 60 MPa, at least 70 MPa, at least 80 MPa, at least 90 MPa, atleast 100 MPa, at least 200 MPa, at least 300 MPa, at least 400 MPa, atleast 500 MPa, at least 600 MPa, at least 700 MPa, at least 800 MPa, atleast 900 MPa, at least 1000 MPa, at least 1500 MPa, or at least 2000MPa. In yet other aspects of this embodiment, a porous materialdisclosed herein exhibits a flexural strength of, e.g., at most 1 MPa,at most 5 MPa, at most 10 MPa, at most 20 MPa, at most 30 MPa, at most40 MPa, at most 50 MPa, at most 60 MPa, at most 70 MPa, at most 80 MPa,at most 90 MPa, at most 100 MPa, at most 200 MPa, at most 300 MPa, atmost 400 MPa, at most 500 MPa, at most 600 MPa, at most 700 MPa, at most800 MPa, at most 900 MPa, at most 1000 MPa, at most 1500 MPa, or at most2000 MPa. In still other aspects of this embodiment, a porous materialdisclosed herein exhibits a flexural strength of, e.g., about 1 MPa toabout 50 MPa, about 1 MPa to about 60 MPa, about 1 MPa to about 70 MPa,about 1 MPa to about 80 MPa, about 1 MPa to about 90 MPa, about 1 MPa toabout 100 MPa, about 10 MPa to about 50 MPa, about 10 MPa to about 60MPa, about 10 MPa to about 70 MPa, about 10 MPa to about 80 MPa, about10 MPa to about 90 MPa, about 10 MPa to about 100 MPa, about 100 MPa toabout 500 MPA, about 300 MPa to about 500 MPA, about 300 MPa to about1000 MPa, about 500 MPa to about 1000 MPa, about 700 MPa to about 1000MPa, about 700 MPa to about 1500 MPa, about 1000 MPa to about 1500 MPa,or about 1200 MPa to about 1500 MPa.

A porous material comprising a matrix defining an array ofinterconnected pores may exhibit high compressibility. Compressibilityrefers to the relative volume change in response to a pressure (or meanstress) change, and is the reciprocal of the bulk modulus.

In an embodiment, a porous material comprising a matrix defining anarray of interconnected pores exhibits high compressibility. In aspectsof this embodiment, a porous material disclosed herein exhibits acompressibility of, e.g., about 0.1 kPa, about 0.5 kPa, about 1 kPa,about 5 kPa, about 10 kPa, about 15 kPa, about 20 kPa, about 30 kPa,about 40 kPa, about 50 kPa, about 60 kPa, about 70 kPa, about 80 kPa,about 90 kPa, or about 100 kPa. In other aspects of this embodiment, aporous material disclosed herein exhibits a compressibility of, e.g., atleast 0.1 kPa, at least 0.5 kPa, at least 1 kPa, at least 5 kPa, atleast 10 kPa, at least 15 kPa, at least 20 kPa, at least 30 kPa, atleast 40 kPa, at least 50 kPa, at least 60 kPa, at least 70 kPa, atleast 80 kPa, at least 90 kPa, or at least 100 kPa. In yet other aspectsof this embodiment, a porous material disclosed herein exhibits acompressibility of, e.g., at most 0.1 kPa, at most 0.5 kPa, at most 1kPa, at most 5 kPa, at most 10 kPa, at most 15 kPa, at most 20 kPa, atmost 30 kPa, at most 40 kPa, at most 50 kPa, at most 60 kPa, at most 70kPa, at most 80 kPa, at most 90 kPa, or at most 100 kPa. In still otheraspects of this embodiment, a porous material disclosed herein exhibitsa compressibility of, e.g., about 0.1 kPa to about 100 kPa, about 0.5kPa to about 100 kPa, about 1 kPa to about 100 kPa, about 5 kPa to about100 kPa, about 10 kPa to about 100 kPa, about 1 kPa to about 30 kPa,about 1 kPa to about 40 kPa, about 1 kPa to about 50 kPa, or about 1 kPato about 60 kPa.

A porous material comprising a matrix defining an array ofinterconnected pores may exhibit low hardness. Hardness refers tovarious properties of an object in the solid phase that gives it highresistance to various kinds of shape change when force is applied.Hardness can be measured using a durometer and expressed using a Shore Ascale, a unitless value that ranges from zero to 100.

In an embodiment, a porous material comprising a matrix defining anarray of interconnected pores exhibits low hardness. In aspects of thisembodiment, a porous material disclosed herein exhibits a Shore Ahardness of, e.g., about 5, about 10, about 15, about 20, about 25,about 30, about 35, about 40, about 45, about 50, about 55, or about 60.In other aspects of this embodiment, a porous material disclosed hereinexhibits a Shore A hardness of, e.g., at least 5, at least 10, at least15, at least 20, at least 25, at least 30, at least 35, at least 40, atleast 45, at least 50, at least 55, or at least 60. In yet other aspectsof this embodiment, a porous material disclosed herein exhibits a ShoreA hardness of, e.g., at most 5, at most 10, at most 15, at most 20, atmost 25, at most 30, at most 35, at most 40, at most 45, at most 50, atmost 55, or at most 60. In still other aspects of this embodiment, aporous material disclosed herein exhibits a Shore A hardness of, e.g.,about 5 to about 60, about 10 to about 50, about 15 to about 45, about20 to about 40, or about 25 to about 35.

A porous material comprising a matrix defining an array ofinterconnected pores may exhibit low thermal conductivity. Thermalconductivity, k, refers to the property of a material that indicates itsability to conduct heat and is measured in watts per Kelvin per meter(W·K⁻¹·m⁻¹). Multiplied by a temperature difference (in K) and an area(in m²), and divided by a thickness (in m) the thermal conductivitypredicts the energy loss (in W) through a piece of material. Thereciprocal of thermal conductivity is thermal resistivity, and ismeasured in Kelvin-meters per watt (K·m·W⁻¹). Thermal conductance refersto the quantity of heat that passes in unit time through a plate ofparticular area and thickness when its opposite faces differ intemperature by one Kelvin. For a plate of thermal conductivity k, area Aand thickness L this is kA/L, measured in W·K⁻¹ (equivalent to: W/° C.).The reciprocal of thermal conductance is thermal resistance [L/(kA)],and is measured in K·W⁻¹ (equivalent to: ° C./W). Heat transfercoefficient (k/L), also known as thermal admittance, refers to thequantity of heat that passes in unit time through unit area of a plateof particular thickness when its opposite faces differ in temperature byone Kelvin, and is measured in W·K⁻¹ m⁻². The reciprocal of heattransfer coefficient is thermal insulance (L/k), and is measured inK·m²W⁻¹.

In an embodiment, a porous material comprising a matrix defining anarray of interconnected pores exhibits low thermal conductivity. Inaspects of this embodiment, a porous material disclosed herein exhibitsa thermal conductivity of, e.g., about 0.010 Wm⁻¹K⁻¹, about 0.025Wm⁻¹K⁻¹, about 0.050 Wm⁻¹K⁻¹, about 0.075 Wm⁻¹K⁻¹, about 0.10 Wm⁻¹K⁻¹,about 0.25 Wm⁻¹K⁻¹, about 0.50 Wm⁻¹K⁻¹, about 0.75 Wm⁻¹K⁻¹, about 1.0Wm⁻¹K⁻¹, about 2.5 Wm⁻¹K⁻¹, about 5.0 Wm⁻¹K⁻¹, about 7.5 Wm⁻¹K⁻¹, orabout 10 Wm⁻¹K⁻¹. In other aspects of this embodiment, a porous materialdisclosed herein exhibits a thermal conductivity of, e.g., at most 0.010Wm⁻¹K⁻¹, at most 0.025 Wm⁻¹K⁻¹, at most 0.050 Wm⁻¹K⁻¹, at most 0.075Wm⁻¹K⁻¹, at most 0.10 Wm⁻¹K⁻¹, at most 0.25 Wm⁻¹K⁻¹, at most 0.50Wm⁻¹K⁻¹, at most 0.75 Wm⁻¹K⁻¹, at most 1.0 Wm⁻¹K⁻¹, at most 2.5 Wm⁻¹K⁻¹,at most 5.0 Wm⁻¹K⁻¹, at most 7.5 Wm⁻¹K⁻¹, or at most 10 Wm⁻¹K⁻¹. In yetother aspects of this embodiment, a porous material disclosed hereinexhibits a thermal conductivity of, e.g., about 0.010 Wm⁻¹K⁻¹ to about0.10 Wm⁻¹K⁻¹, about 0.010 Wm⁻¹K⁻¹ to about 1.0 Wm⁻¹K⁻¹, about 0.010Wm⁻¹K⁻¹ to about 10 Wm⁻¹K⁻¹, about 0.050 Wm⁻¹K⁻¹ to about 0.50 Wm⁻¹K⁻¹,about 0.050 Wm⁻¹K⁻¹ to about 5.0 Wm⁻¹K⁻¹, about 0.010 Wm⁻¹K⁻¹ to about0.050 Wm⁻¹K⁻¹, about 0.025 Wm⁻¹K⁻¹ to about 0.075 Wm⁻¹K⁻¹, about 0.050Wm⁻¹K⁻¹ to about 0.10 Wm⁻¹K⁻¹, about 0.075 Wm⁻¹K⁻¹ to about 0.25Wm⁻¹K⁻¹, about 0.10 Wm⁻¹K⁻¹ to about 0.50 Wm⁻¹K⁻¹, about 0.25 Wm⁻¹K⁻¹ toabout 0.75 Wm⁻¹K⁻¹, about 0.50 Wm⁻¹K⁻¹ to about 1.0 Wm⁻¹K⁻¹, about 0.75Wm⁻¹K⁻¹ to about 2.5 Wm⁻¹K⁻¹, about 1.0 Wm⁻¹K⁻¹ to about 5.0 Wm⁻¹K⁻¹,about 2.5 Wm⁻¹K⁻¹ to about 7.5 Wm⁻¹K⁻¹, or about 5.0 Wm⁻¹K⁻¹ to about 10Wm⁻¹K⁻¹.

A porous material comprising a matrix includes pores having a shapesufficient to enable the desired function of the porous material. Usefulpore shapes include, without limitation, roughly spherical, perfectlyspherical, dodecahedrons (such as pentagonal dodecahedrons), andellipsoids. For example, in certain biomedical applications, the shapeof the pores should be in a form sufficient to support aspects tissuegrowth into the array of interconnected pores, thereby supportingaspects of tissue growth such as, e.g., cell migration, cellproliferation, cell differentiation, nutrient exchange, and/or wasteremoval. As another example, in filtration applications, the shape ofthe pores should be in a form that facilitates removal unwantedsubstances from the filtered material.

A porous material comprising a matrix includes pores having a roundnesssufficient to enable the desired function of the porous material. Asused herein, “roundness” is defined as (6×V)/(π×D³), where V is thevolume and D is the diameter. Any pore roundness is useful with theproviso that the pore roundness is sufficient to enable the desiredfunction of the porous material. For example, in certain biomedicalapplications, pore roundness should be sufficient to support aspectstissue growth into the array of interconnected pores, thereby supportingaspects of tissue growth such as, e.g., cell migration, cellproliferation, cell differentiation, nutrient exchange, and/or wasteremoval. As another example, in filtration applications, pore roundnessshould be sufficient to facilitate removal unwanted substances from thefiltered material.

A porous material comprising a matrix may be formed in such a mannerthat substantially all the pores in the matrix have a similar diameter.As used herein, the term “substantially”, when used to describe pores,refers to at least 90% of the pores within the matrix such as, e.g., atleast 95% or at least 97% of the pores. As used herein, the term“similar diameter”, when used to describe pores, refers to a differencein the diameters of the two pores that is less than about 20% of thelarger diameter. As used herein, the term “diameter”, when used todescribe pores, refers to the longest line segment that can be drawnthat connects two points within the pore, regardless of whether the linepasses outside the boundary of the pore. For example, in certainbiomedical applications, pore diameter should be sufficient to supportaspects tissue growth into the array of interconnected pores, therebysupporting aspects of tissue growth such as, e.g., cell migration, cellproliferation, cell differentiation, nutrient exchange, and/or wasteremoval. As another example, in filtration applications, pore diametershould be sufficient to facilitate removal unwanted substances from thefiltered material.

A porous material comprising a matrix is formed in such a manner thatthe diameter of the connections between pores is sufficient to enablethe desired function of the porous material. As used herein, the term“diameter”, when describing the connection between pores, refers to thediameter of the cross-section of the connection between two pores in theplane normal to the line connecting the centroids of the two pores,where the plane is chosen so that the area of the cross-section of theconnection is at its minimum value. As used herein, the term “diameterof a cross-section of a connection” refers to the average length of astraight line segment that passes through the center, or centroid (inthe case of a connection having a cross-section that lacks a center), ofthe cross-section of a connection and terminates at the periphery of thecross-section. As used herein, the term “substantially”, when used todescribe the connections between pores refers to at least 90% of theconnections made between each pore comprising the matrix, such as, e.g.,at least 95% or at least 97% of the connections. For example, in certainbiomedical applications, the diameter of the connections between poresshould be sufficient to support aspects tissue growth into the array ofinterconnected pores, thereby supporting aspects of tissue growth suchas, e.g., cell migration, cell proliferation, cell differentiation,nutrient exchange, and/or waste removal. As another example, infiltration applications, the diameter of the connections between poresshould be sufficient to facilitate removal unwanted substances from thefiltered material.

Thus, in an embodiment, a porous material comprising matrix defining anarray of interconnected pores includes pores having a roundnesssufficient to enable the desired function of the porous material. Inaspects of this embodiment, a porous material disclosed herein includespores having a roundness of, e.g., about 0.1, about 0.2, about 0.3,about 0.4, about 0.5, about 0.6, about 0.7, about 0.8, about 0.9, orabout 1.0. In other aspects of this embodiment, a porous materialdisclosed herein includes pores having a roundness of, e.g., at least0.1, at least 0.2, at least 0.3, at least 0.4, at least 0.5, at least0.6, at least 0.7, at least 0.8, at least 0.9, or at least 1.0. In yetother aspects of this embodiment, a porous material disclosed hereinincludes pores having a roundness of, e.g., at most 0.1, at most 0.2, atmost 0.3, at most 0.4, at most 0.5, at most 0.6, at most 0.7, at most0.8, at most 0.9, or at most 1.0. In still other aspects of thisembodiment, a porous material disclosed herein includes pores having aroundness of, e.g., about 0.1 to about 1.0, about 0.2 to about 1.0,about 0.3 to about 1.0, about 0.4 to about 1.0, about 0.5 to about 1.0,about 0.6 to about 1.0, about 0.7 to about 1.0, about 0.8 to about 1.0,about 0.9 to about 1.0, about 0.1 to about 0.9, about 0.2 to about 0.9,about 0.3 to about 0.9, about 0.4 to about 0.9, about 0.5 to about 0.9,about 0.6 to about 0.9, about 0.7 to about 0.9, about 0.8 to about 0.9,about 0.1 to about 0.8, about 0.2 to about 0.8, about 0.3 to about 0.8,about 0.4 to about 0.8, about 0.5 to about 0.8, about 0.6 to about 0.8,about 0.7 to about 0.8, about 0.1 to about 0.7, about 0.2 to about 0.7,about 0.3 to about 0.7, about 0.4 to about 0.7, about 0.5 to about 0.7,about 0.6 to about 0.7, about 0.1 to about 0.6, about 0.2 to about 0.6,about 0.3 to about 0.6, about 0.4 to about 0.6, about 0.5 to about 0.6,about 0.1 to about 0.5, about 0.2 to about 0.5, about 0.3 to about 0.5,or about 0.4 to about 0.5.

In another embodiment, substantially all pores within a porous materialcomprising a matrix have a similar diameter sufficient to enable thedesired function of the porous material. In aspects of this embodiment,at least 90% of all pores within a porous material comprising a matrixhave a similar diameter, at least 95% of all pores within a porousmaterial comprising a matrix have a similar diameter, or at least 97% ofall pores within a porous material comprising a matrix have a similardiameter. In another aspect of this embodiment, difference in thediameters of two pores is, e.g., less than about 20% of the largerdiameter, less than about 15% of the larger diameter, less than about10% of the larger diameter, or less than about 5% of the largerdiameter.

In another embodiment, a porous material comprising a matrix defining anarray of interconnected pores includes pores having a mean diametersufficient to enable the desired function of the porous material. Inaspects of this embodiment, a porous material comprising a matrixincludes pores having mean pore diameter of, e.g., about 50 μm, about 75μm, about 100 μm, about 150 μm, about 200 μm, about 250 μm, about 300μm, about 350 μm, about 400 μm, about 450 μm, or about 500 μm. In otheraspects, a porous material disclosed herein includes pores having meanpore diameter of, e.g., about 500 μm, about 600 μm, about 700 μm, about800 μm, about 900 μm, about 1000 μm, about 1500 μm, about 2000 μm, about2500 μm, or about 3000 μm. In yet other aspects of this embodiment, aporous material disclosed herein includes pores having mean porediameter of, e.g., at least 50 μm, at least 75 μm, at least 100 μm, atleast 150 μm, at least 200 μm, at least 250 μm, at least 300 μm, atleast 350 μm, at least 400 μm, at least 450 μm, or at least 500 μm. Instill other aspects, a porous material disclosed herein includes poreshaving mean pore diameter of, e.g., at least 500 μm, at least 600 μm, atleast 700 μm, at least 800 μm, at least 900 μm, at least 1000 μm, atleast 1500 μm, at least 2000 μm, at least 2500 μm, or at least 3000 μm.In further aspects of this embodiment, a porous material disclosedherein includes pores having mean pore diameter of, e.g., at most 50 μm,at most 75 μm, at most 100 μm, at most 150 μm, at most 200 μm, at most250 μm, at most 300 μm, at most 350 μm, at most 400 μm, at most 450 μm,or at most 500 μm. In yet further aspects of this embodiment, a porousmaterial disclosed herein includes pores having mean pore diameter of,e.g., at most 500 μm, at most 600 μm, at most 700 μm, at most 800 μm, atmost 900 μm, at most 1000 μm, at most 1500 μm, at most 2000 μm, at most2500 μm, or at most 3000 μm. In still further aspects of thisembodiment, a porous material disclosed herein includes pores havingmean pore diameter in a range from, e.g., about 300 μm to about 600 μm,about 200 μm to about 700 μm, about 100 μm to about 800 μm, about 500 μmto about 800 μm, about 50 μm to about 500 μm, about 75 μm to about 500μm, about 100 μm to about 500 μm, about 200 μm to about 500 μm, about300 μm to about 500 μm, about 50 μm to about 1000 μm, about 75 μm toabout 1000 μm, about 100 μm to about 1000 μm, about 200 μm to about 1000μm, about 300 μm to about 1000 μm, about 50 μm to about 1000 μm, about75 μm to about 3000 μm, about 100 μm to about 3000 μm, about 200 μm toabout 3000 μm, or about 300 μm to about 3000 μm.

In another embodiment, a porous material comprising a matrix defining anarray of interconnected pores includes pores having a mean matrix strutthickness sufficient to enable the desired function of the porousmaterial. In aspects of this embodiment, a porous material disclosedherein includes pores having a mean matrix strut thickness of, e.g.,about 10 μm, about 20 μm, about 30 μm, about 40 μm, about 50 μm, about60 μm, about 70 μm, about 80 μm, about 90 μm, about 100 μm, about 110μm, about 120 μm, about 130 μm, about 140 μm, about 150 μm, about 160μm, about 170 μm, about 180 μm, about 190 μm, or about 200 μm. In otheraspects of this embodiment, a porous material disclosed herein includespores having a mean matrix strut thickness of, e.g., at least 10 μm, atleast 20 μm, at least 30 μm, at least 40 μm, at least 50 μm, at least 60μm, at least 70 μm, at least 80 μm, at least 90 μm, at least 100 μm, atleast 110 μm, at least 120 μm, at least 130 μm, at least 140 μm, atleast 150 μm, at least 160 μm, at least 170 μm, at least 180 μm, atleast 190 μm, or at least 200 μm. In yet other aspects of thisembodiment, a porous material disclosed herein includes pores having amean matrix strut thickness of, e.g., at most 10 μm, at most 20 μm, atmost 30 μm, at most 40 μm, at most 50 μm, at most 60 μm, at most 70 μm,at most 80 μm, at most 90 μm, at most 100 μm, at most 110 μm, at most120 μm, at most 130 μm, at most 140 μm, at most 150 μm, at most 160 μm,at most 170 μm, at most 180 μm, at most 190 μm, or at most 200 μm. Instill aspects of this embodiment, a porous material disclosed hereinincludes pores having a mean matrix strut thickness of, e.g., about 50μm to about 110 μm, about 50 μm to about 120 μm, about 50 μm to about130 μm, about 50 μm to about 140 μm, about 50 μm to about 150 μm, about60 μm to about 110 μm, about 60 μm to about 120 μm, about 60 μm to about130 μm, about 60 μm to about 140 μm, about 70 μm to about 110 μm, about70 μm to about 120 μm, about 70 μm to about 130 μm, or about 70 μm toabout 140 μm.

In another embodiment, a porous material comprising a matrix defining anarray of interconnected pores includes pores connected to a plurality ofother pores. In aspects of this embodiment, a porous material disclosedherein comprises a mean pore connectivity, e.g., about two other pores,about three other pores, about four other pores, about five other pores,about six other pores, about seven other pores, about eight other pores,about nine other pores, about ten other pores, about 11 other pores, orabout 12 other pores. In other aspects of this embodiment, a porousmaterial disclosed herein comprises a mean pore connectivity, e.g., atleast two other pores, at least three other pores, at least four otherpores, at least five other pores, at least six other pores, at leastseven other pores, at least eight other pores, at least nine otherpores, at least ten other pores, at least 11 other pores, or at least 12other pores. In yet other aspects of this embodiment, a porous materialdisclosed herein comprises a mean pore connectivity, e.g., at most twoother pores, at most three other pores, at most four other pores, atmost five other pores, at most six other pores, at most seven otherpores, at most eight other pores, at most nine other pores, at most tenother pores, at most 11 other pores, or at most 12 other pores.

In still other aspects of this embodiment, a porous material disclosedherein includes pores connected to, e.g., about two other pores to about12 other pores, about two other pores to about 11 other pores, about twoother pores to about ten other pores, about two other pores to aboutnine other pores, about two other pores to about eight other pores,about two other pores to about seven other pores, about two other poresto about six other pores, about two other pores to about five otherpores, about three other pores to about 12 other pores, about threeother pores to about 11 other pores, about three other pores to aboutten other pores, about three other pores to about nine other pores,about three other pores to about eight other pores, about three otherpores to about seven other pores, about three other pores to about sixother pores, about three other pores to about five other pores, aboutfour other pores to about 12 other pores, about four other pores toabout 11 other pores, about four other pores to about ten other pores,about four other pores to about nine other pores, about four other poresto about eight other pores, about four other pores to about seven otherpores, about four other pores to about six other pores, about four otherpores to about five other pores, about five other pores to about 12other pores, about five other pores to about 11 other pores, about fiveother pores to about ten other pores, about five other pores to aboutnine other pores, about five other pores to about eight other pores,about five other pores to about seven other pores, or about five otherpores to about six other pores.

In another embodiment, a porous material comprising a matrix defining anarray of interconnected pores includes pores where the diameter of theconnections between pores is sufficient to enable the desired functionof the porous material. In aspects of this embodiment, a porous materialdisclosed herein includes pores where the diameter of the connectionsbetween pores is, e.g., about 10% the mean pore diameter, about 20% themean pore diameter, about 30% the mean pore diameter, about 40% the meanpore diameter, about 50% the mean pore diameter, about 60% the mean porediameter, about 70% the mean pore diameter, about 80% the mean porediameter, or about 90% the mean pore diameter. In other aspects of thisembodiment, a porous material disclosed herein includes pores where thediameter of the connections between pores is, e.g., at least 10% themean pore diameter, at least 20% the mean pore diameter, at least 30%the mean pore diameter, at least 40% the mean pore diameter, at least50% the mean pore diameter, at least 60% the mean pore diameter, atleast 70% the mean pore diameter, at least 80% the mean pore diameter,or at least 90% the mean pore diameter. In yet other aspects of thisembodiment, a porous material disclosed herein includes pores where thediameter of the connections between pores is, e.g., at most 10% the meanpore diameter, at most 20% the mean pore diameter, at most 30% the meanpore diameter, at most 40% the mean pore diameter, at most 50% the meanpore diameter, at most 60% the mean pore diameter, at most 70% the meanpore diameter, at most 80% the mean pore diameter, or at most 90% themean pore diameter.

In still other aspects of this embodiment, a porous material disclosedherein includes pores where the diameter of the connections betweenpores is, e.g., about 10% to about 90% the mean pore diameter, about 15%to about 90% the mean pore diameter, about 20% to about 90% the meanpore diameter, about 25% to about 90% the mean pore diameter, about 30%to about 90% the mean pore diameter, about 35% to about 90% the meanpore diameter, about 40% to about 90% the mean pore diameter, about 10%to about 80% the mean pore diameter, about 15% to about 80% the meanpore diameter, about 20% to about 80% the mean pore diameter, about 25%to about 80% the mean pore diameter, about 30% to about 80% the meanpore diameter, about 35% to about 80% the mean pore diameter, about 40%to about 80% the mean pore diameter, about 10% to about 70% the meanpore diameter, about 15% to about 70% the mean pore diameter, about 20%to about 70% the mean pore diameter, about 25% to about 70% the meanpore diameter, about 30% to about 70% the mean pore diameter, about 35%to about 70% the mean pore diameter, about 40% to about 70% the meanpore diameter, about 10% to about 60% the mean pore diameter, about 15%to about 60% the mean pore diameter, about 20% to about 60% the meanpore diameter, about 25% to about 60% the mean pore diameter, about 30%to about 60% the mean pore diameter, about 35% to about 60% the meanpore diameter, about 40% to about 60% the mean pore diameter, about 10%to about 50% the mean pore diameter, about 15% to about 50% the meanpore diameter, about 20% to about 50% the mean pore diameter, about 25%to about 50% the mean pore diameter, about 30% to about 50% the meanpore diameter, about 10% to about 40% the mean pore diameter, about 15%to about 40% the mean pore diameter, about 20% to about 40% the meanpore diameter, about 25% to about 40% the mean pore diameter, or about30% to about 40% the mean pore diameter.

The present specification discloses, in part, a porous materialcomprising a matrix defining an array of interconnected pores having aporosity sufficient to enable the desired function of the porousmaterial. As used herein, the term “porosity” refers to the amount ofvoid space in a porous material comprising a matrix. As such, the totalvolume of a porous material comprising a matrix disclosed herein isbased upon the matrix space and the void space. For example, in certainbiomedical applications, the porosity of the porous material should besufficient to support aspects tissue growth into the array ofinterconnected pores, thereby supporting aspects of tissue growth suchas, e.g., cell migration, cell proliferation, cell differentiation,nutrient exchange, and/or waste removal. As another example, infiltration applications, the porosity of the porous material should besufficient to facilitate removal unwanted substances from the filteredmaterial.

In aspects of this embodiment, a porous material comprising a matrixdefining an array of interconnected pores has a porosity of, e.g., about40% of the total volume of a matrix, about 50% of the total volume of amatrix, about 60% of the total volume of a matrix, about 70% of thetotal volume of a matrix, about 80% of the total volume of a matrix,about 90% of the total volume of a matrix, about 95% of the total volumeof a matrix, or about 97% of the total volume of a matrix. In otheraspects of this embodiment, a porous material disclosed herein has aporosity of, e.g., at least 40% of the total volume of a matrix, atleast 50% of the total volume of a matrix, at least 60% of the totalvolume of a matrix, at least 70% of the total volume of a matrix, atleast 80% of the total volume of a matrix, at least 90% of the totalvolume of a matrix, at least 95% of the total volume of a matrix, or atleast 97% of the total volume of a matrix. In yet other aspects of thisembodiment, a porous material disclosed herein has a porosity of, e.g.,at most 40% of the total volume of a matrix, at most 50% of the totalvolume of a matrix, at most 60% of the total volume of a matrix, at most70% of the total volume of a matrix, at most 80% of the total volume ofa matrix, at most 90% of the total volume of a matrix, at most 95% ofthe total volume of a matrix, or at most 97% of the total volume of amatrix. In yet other aspects of this embodiment, a porous materialdisclosed herein has a porosity of, e.g., about 40% to about 97% of thetotal volume of a matrix, about 50% to about 97% of the total volume ofa matrix, about 60% to about 97% of the total volume of a matrix, about70% to about 97% of the total volume of a matrix, about 80% to about 97%of the total volume of a matrix, about 90% to about 97% of the totalvolume of a matrix, about 40% to about 95% of the total volume of amatrix, about 50% to about 95% of the total volume of a matrix, about60% to about 95% of the total volume of a matrix, about 70% to about 95%of the total volume of a matrix, about 80% to about 95% of the totalvolume of a matrix, about 90% to about 95% of the total volume of amatrix, about 40% to about 90% of the total volume of a matrix, about50% to about 90% of the total volume of a matrix, about 60% to about 90%of the total volume of a matrix, about 70% to about 90% of the totalvolume of a matrix, or about 80% to about 90% of the total volume of amatrix.

The present specification discloses, in part, a porous materialcomprising a matrix defining an array of interconnected pores having amean open pore value and/or a mean closed pore value sufficient toenable the desired function of the porous material. As used herein, theterm “mean open pore value” or “mean open pore” refers to the averagenumber of pores that are connected to at least one other pore present inthe matrix. As used herein, the term “mean closed pore value” or “meanclosed pore” refers to the average number of pores that are notconnected to any other pores present in the matrix. For example, incertain biomedical applications, the array of interconnected poresshould have a mean open pore value and/or a mean closed pore valuesufficient to support aspects tissue growth into the array ofinterconnected pores, thereby supporting aspects of tissue growth suchas, e.g., cell migration, cell proliferation, cell differentiation,nutrient exchange, and/or waste removal. As another example, infiltration applications, the array of interconnected pores should have amean open pore value and/or a mean closed pore value sufficient tofacilitate removal unwanted substances from the filtered material.

In aspects of this embodiment, a porous material comprising a matrixdefining an array of interconnected pores has a mean open pore value of,e.g., about 70%, about 75%, about 80%, about 85%, about 90%, about 95%,or about 97%. In other aspects of this embodiment, a porous materialdisclosed herein has a mean open pore value of, e.g., at least 70%, atleast 75%, at least 80%, at least 85%, at least 90%, at least 95%, or atleast 97%. In yet other aspects of this embodiment, a porous materialdisclosed herein has a mean open pore value of, e.g., at most 70%, atmost 75%, at most 80%, at most 85%, at most 90%, at most 95%, or at most97%. In still aspects of this embodiment, a porous material disclosedherein has a mean open pore value of, e.g., about 70% to about 90%,about 75% to about 90%, about 80% to about 90%, about 85% to about 90%,about 70% to about 95%, about 75% to about 95%, about 80% to about 95%,about 85% to about 95%, about 90% to about 95%, about 70% to about 97%,about 75% to about 97%, about 80% to about 97%, about 85% to about 97%,or about 90% to about 97%.

In another embodiment, a porous material comprising a matrix defining anarray of interconnected pores has a mean closed pore value sufficient toenable the desired function of the porous material. In aspects of thisembodiment, a porous material disclosed herein has a mean closed porevalue of, e.g., about 5%, about 10%, about 15%, or about 20%. In otheraspects of this embodiment, a porous material disclosed herein has amean closed pore value of, e.g., about 5% or less, about 10% or less,about 15% or less, or about 20% or less. In yet other aspects of thisembodiment, a porous material disclosed herein has a mean closed porevalue of, e.g., about 5% to about 10%, about 5% to about 15%, or about5% to about 20%.

The present specification discloses, in part, a porous materialcomprising a matrix defining an array of interconnected pores having avoid space sufficient to enable the desired function of the porousmaterial. As used herein, the term “void space” refers to actual orphysical space in a porous material comprising a matrix. As such, thetotal volume of a porous material comprising a matrix disclosed hereinis based upon the matrix space and the void space. For example, incertain biomedical applications, the void space should be sufficient tosupport aspects tissue growth into the array of interconnected pores,thereby supporting aspects of tissue growth such as, e.g., cellmigration, cell proliferation, cell differentiation, nutrient exchange,and/or waste removal. As another example, in filtration applications,the void space should be sufficient to facilitate removal unwantedsubstances from the filtered material.

In aspects of this embodiment, a porous material comprising a matrixdefining an array of interconnected pores has a void space of, e.g.,about 50% of the total volume of a matrix, about 60% of the total volumeof a matrix, about 70% of the total volume of a matrix, about 80% of thetotal volume of a matrix, about 90% of the total volume of a matrix,about 95% of the total volume of a matrix, or about 97% of the totalvolume of a matrix. In other aspects of this embodiment, a porousmaterial disclosed herein has a void space of, e.g., at least 50% of thetotal volume of a matrix, at least 60% of the total volume of a matrix,at least 70% of the total volume of a matrix, at least 80% of the totalvolume of a matrix, at least 90% of the total volume of a matrix, atleast 95% of the total volume of a matrix, or at least 97% of the totalvolume of a matrix. In yet other aspects of this embodiment, a porousmaterial disclosed herein has a void space of, e.g., at most 50% of thetotal volume of a matrix, at most 60% of the total volume of a matrix,at most 70% of the total volume of a matrix, at most 80% of the totalvolume of a matrix, at most 90% of the total volume of a matrix, at most95% of the total volume of a matrix, or at most 97% of the total volumeof a matrix. In yet other aspects of this embodiment, a porous materialdisclosed herein has a void space of, e.g., about 50% to about 97% ofthe total volume of a matrix, about 60% to about 97% of the total volumeof a matrix, about 70% to about 97% of the total volume of a matrix,about 80% to about 97% of the total volume of a matrix, about 90% toabout 97% of the total volume of a matrix, about 50% to about 95% of thetotal volume of a matrix, about 60% to about 95% of the total volume ofa matrix, about 70% to about 95% of the total volume of a matrix, about80% to about 95% of the total volume of a matrix, about 90% to about 95%of the total volume of a matrix, about 50% to about 90% of the totalvolume of a matrix, about 60% to about 90% of the total volume of amatrix, about 70% to about 90% of the total volume of a matrix, or about80% to about 90% of the total volume of a matrix.

A porous material comprising a matrix defining an array ofinterconnected pores generally has a low level of microporosity. As usedherein, the term “microporosity” refers to a measure of the presence ofsmall micropores within a porous material comprising a matrix itself (asopposed to the pores defined by a matrix). In some embodiments, all orsubstantially all of the micropores in a porous material disclosedherein are between about 0.1 μm and about 5 μm, such as between about0.1 μm and about 3 μm or between about 0.1 μm and about 2 μm. The term“low level of microporosity” means that micropores represent less than2% of the volume of a porous material disclosed herein, as measured bymeasuring the percentage void space in a cross-section through a matrix.

The shape, roundness, and diameter of pores, the connections betweenpores, the total volume of the porous material, the void volume, and thematrix volume can all be assessed using scanning electron microscopy.See, e.g., FIGS. 1A and 1B.

The disclosed porous materials are not only useful in all applicationscurrently fulfilled by polyurethane-based materials, but also in manyadditional applications not ideally suitable for polyurethane-basedmaterials. Non-limiting examples of applications for the porousmaterials disclosed herein include cushion underlay for carpets;upholstery padding for furniture and vehicle interior components likeseats, headrests, armrests, roof liners, dashboards, and instrumentpanels; material for pillows, mattress bedding, toppers, and cores;sponges; mid- and outsoles of footwear; vehicle fascia and otherexterior parts; fabric coatings as synthetic fibers; packaging material;integral skin form for vehicle interiors; sound-deadening material;insulating material such as, e.g., panel or spray insulation inbuildings, water heaters, refrigerated transport, and commercial andresidential refrigeration; structural components; simulated wood;cleaning material such as, e.g., wipes, swabs, and abrasives; andfiltration materials for air and/or liquid filtration; filters forseparating or cleaning material present in a chemically aggressiveenvironment; and light weight armor material.

The present specification discloses, in part, a porous materialcomprising a matrix defining an array of interconnected pores having alow thermal conductivity and/or high acoustic absorption. Such a porousmaterial is useful in insulation materials such as, e.g., panel or sprayinsulation in buildings, water heaters, refrigerated transport, andcommercial and residential refrigeration. Additionally, such a porousmaterial may be insoluble or substantially insoluble in solvents, acids,and/or bases used during the application of the insulating material orexposed to once installed. An insulating material useful for thermalinsulation will typically be made from a thermoplastic polymer, such as,e.g., polystyrene. The porous material may be made in sheet formtypically from about 0.5 cm to about 10 cm in thickness with a porosityof about 70 to about 95% with at least partly open pores withinterconnection diameter from approximately 1.0 μm to approximately 150μm and a mean pore size of about 50 μm to about 800 μm.

The present specification discloses, in part, a porous materialcomprising a matrix defining an array of interconnected pores useful inthe manufacturing of cleaning materials, such as, e.g., wipes, swabs,and abrasives, and including personal hygiene products. Such porouscleaning materials are typically designed for particular applications byoptimizing absorption or the affinity of the polymer and porosity of thematrix for the material to be cleaned. For instance, for industrialcleaning, acidic aqueous solutions may be cleaned with a porous materialcomprising a lightly crosslinked polymer having basic functionalities onthe backbone or pendants, such as lightly crosslinked chitosan orpoly(ethyleneamine), which would swell in the acidic medium. Likewisebasic aqueous spills can be best cleaned by a porous material comprisinga lightly crosslinked poly(acrylic acid). In addition, amphiphilicaqueous spills can be best cleaned by a porous material comprising alightly crosslinked poly(ethyleneglycol), which readily absorbs bothwater and some organic solvents such as, e.g., dioxane anddichloromethane. Lastly, hydrophobic spills can be cleaned usingpolymers that readily swell in and absorb hydrophobic materials, yet arenot dissolved by them.

The present specification discloses, in part, a porous materialcomprising a matrix defining an array of interconnected pores useful asfiltration materials for air and/or liquid filtration. Such porousfiltration materials have Porosities for filters may vary from about 80%to approximately 99.9% and average pore size can vary from about 1 μm toabout 2000 μm. The porous material must be predominantly open celled andwith interconnection diameters varying from about 1 μm to about 1800 μm.Such porous filtration materials are typically designed for particularapplications by optimizing the affinity of the polymer and porosity ofthe matrix for the material to be filtration. For example, hydrophilicfiltration materials, such as, e.g., filtration materials comprising amatrix composed of fluoropolymer thermosets or poly(vinyl)-basedthermoplastics, are readily wetted with aqueous solutions. Hydrophobicfilters materials, such as, e.g., filtration materials comprising amatrix composed of cellulose-based thermoplastics or poly(vinyl)-basedthermoplastics, are readily wet in low surface-tension liquids, such asorganic solvents and silicone oil and are best suited for gas filtrationand venting applications. In venting applications, air can pass throughthese filters without allowing the passage of water. Other filtrationapplications include the filtering of low surface tension and highsurface tension solutions, as well as separation of low surface tensionfrom high surface tension mediums.

The present specification discloses, in part, a porous materialcomprising a matrix defining an array of interconnected pores useful asfiltration materials in a chemically aggressive environment. Such porousfiltration materials have porosities for filters may vary from about 80%to approximately 99.9% and average pore size can vary from about 300 μmto about 5000 μm. The porous material must be predominantly open celledand with interconnection diameters varying from about 300 μm to about5,000 μm. Such porous filtration materials are typically designed forparticular applications by optimizing the affinity of the polymer andporosity of the matrix for the material to be filtration. For example,such filtration materials comprising a matrix composed of fluoropolymerthermosets.

The present specification discloses, in part, a porous materialcomprising a matrix defining an array of interconnected pores havingthermally stability. Such a porous material is useful in light weightarmor materials like a component of a flak jacket, bullet-proof vest, orarmor panels for a vehicle. A porous filtration material suitable as alight weight armor material typically comprises low carbon contentmaterials or other non-combustible materials, such as, e.g.,silicone-based elastomers, fluorosilicone-based elastomers, and/orfluoropolymer thermosets. The addition of certain ceramic nanopowderscan help retard the projectile or shrapnel with aid of high density highyield strength particulate.

The present specification discloses, in part, a porous materialcomprising a substantially non-degradable, biocompatible matrix definingan array of interconnected pores. Such a porous material is useful inbiomedical materials like a component of a medical device, scaffolds(templates) for tissue engineering/regeneration, wound dressings, drugrelease matrixes, membranes for separations and filtration, sterilefilters, artificial kidneys, absorbents, hemostatic devices, wherebiocompatibility and resistance to biodegradation are important. Forexample, the disclosed porous material comprising a substantiallynon-degradable, biocompatible, matrix has high porosity andinterconnected pore structures that favor biomedical applicationsdesiring tissue growth into the porous material, such as, e.g., byfacilitating cell migration, cell proliferation, cell differentiation,nutrient exchange, and/or waste removal.

A porous material disclosed herein can be implanted into the soft tissueof an animal. Such a porous material may be completely implanted intothe soft tissue of an animal body (i.e., the entire material is withinthe body), or the device may be partially implanted into an animal body(i.e., only part of the material is implanted within an animal body, theremainder of the material being located outside of the animal body). Aporous material disclosed herein can also be affixed to one or more softtissues of an animal, typically to the skin of an animal body. Forexample, a strip of porous material can be placed subcutaneouslyunderneath a healing wound or incision to prevent the fibrous tissuefrom aligning and thereby reducing or preventing scar formation.

As used herein, the term “non-degradable” refers to a material that isnot prone to degrading, decomposing, or breaking down to any substantialor significant degree while implanted in the host. Non-limiting examplesof substantial non-degradation include less than 10% degradation of aporous material over a time period measured, less than 5% degradation ofa porous material over a time period measured, less than 3% degradationof a porous material over a time period measured, less than 1%degradation of a porous material over a time period measured. As usedherein, the term “biocompatible” refers to a material's ability toperform its intended function, with a desired degree of incorporation inthe host, without eliciting any undesirable local or systemic effects inthat host.

In an embodiment, a porous material comprising a matrix defining anarray of interconnected pores may, or may not be, substantiallynon-degradable. In aspects of this embodiment, a porous materialdisclosed herein is substantially non-degradable for, e.g., about fiveyears, about ten years, about 15 years, about 20 years, about 25 years,about 30 years, about 35 years, about 40 years, about 45 years, or about50 years. In other aspects of this embodiment, a porous materialdisclosed herein is substantially non-degradable for, e.g., at leastfive years, at least ten years, at least 15 years, at least 20 years, atleast 25 years, at least 30 years, at least 35 years, at least 40 years,at least 45 years, or at least 50 years. In yet other aspects of thisembodiment, a porous material disclosed herein exhibits less than 5%degradation, less than 3% degradation, or less than 1% degradation overfor, e.g., about five years, about ten years, about 15 years, about 20years, about 25 years, about 30 years, about 35 years, about 40 years,about 45 years, or about 50 years. In still other aspects of thisembodiment, a porous material disclosed herein exhibits less than 5%degradation, less than 3% degradation, or less than 1% degradation overfor, e.g., at least five years, at least ten years, at least 15 years,at least 20 years, at least 25 years, at least 30 years, at least 35years, at least 40 years, at least 45 years, or at least 50 years.

In another embodiment, a porous material comprising a matrix defining anarray of interconnected pores may, or may not be, substantiallybiocompatible. In aspects of this embodiment, a porous materialdisclosed herein is substantially biocompatible for, e.g., at least fiveyears, at least ten years, at least 15 years, at least 20 years, atleast 25 years, at least 30 years, at least 35 years, at least 40 years,at least 45 years, or at least 50 years.

The present specification discloses in part, methods of making a porousmaterial disclosed herein. The porous materials disclosed herein can beformed as a separate component or can be integrated into a basematerial.

In one aspect, a method of making a porous material comprises the stepsof: a) coating porogens with a matrix material base to form a matrixmaterial-coated porogen mixture; b) treating the matrix material-coatedporogen mixture to allow fusing of the porogens to form a porogenscaffold and curing or hardening of the matrix; c) removing the porogenscaffold, wherein porogen scaffold removal results in a porous material,the porous material comprising a matrix defining an array ofinterconnected pores.

In another aspect, a method of making a porous material comprises thesteps of a) coating porogens with a matrix material base to form amatrix material-coated porogen mixture; b) packing porogens into a mold;c) treating the matrix material-coated porogen mixture to allow fusingof the porogens to form a porogen scaffold and curing or hardening ofthe matrix material; d) removing the porogen scaffold, wherein porogenscaffold removal results in a porous material, the porous materialcomprising a matrix defining an array of interconnected pores.

As used herein, the term “matrix material base” is synonymous with“matrix base”, “material base”, “uncured matrix material”, “uncuredmatrix” and “uncured material” and refers to a material disclosedherein, such as, e.g., a thermoset polymer, an elastomer, or athermoplastic elastomer, that is in its uncured state; or a materialdisclosed herein, such as, e.g., a thermoplastic polymer, that is in itsfluid or soft state.

As used herein, the term “porogen” refers to any structure that can beused to create a porogen scaffold that is removable after a matrix isformed under conditions that do not destroy the matrix. Porogens can bemade of any material having a glass transition temperature (T_(g)) ormelting temperature (T_(m)) from about 30° C. to about 100° C. Inaddition, porogens useful to practice aspects of the presentspecification should be soluble in hydrophilic solvents such as, e.g.,water, dimethyl sulfoxide (DMSO), methylene chloride, chloroform, andacetone. However, porogens useful to practice aspects of the presentspecification should not be soluble in aromatic solvents like xylene,chlorinated solvents like dichloromethane, or any other solvent used todisperse uncured matrix material base. Exemplary porogens suitable foruse in the methods disclosed herein, include, without limitation, salts,such as, e.g., sodium chloride, potassium chloride, sodium fluoride,potassium fluoride, sodium iodide, sodium nitrate, sodium sulfate,sodium iodate, and/or mixtures thereof; sugars and/or its derivatives,such as, e.g., glucose, fructose, sucrose, lactose, maltose, saccharin,and/or mixtures thereof; polysaccharides and their derivatives, such as,e.g., cellulose and hydroxyethylcellulose; waxes, such as, e.g.,paraffin, beeswax, and/or mixtures thereof; other water solublechemicals, such as, e.g., sodium hydroxide; naphthalene; polymers, suchas, e.g., poly(alkylene oxide), poly(acrylamide), poly(acrylic acid),poly(acrylamide-co-acrylic acid),poly(acrylamide-co-diallyldimethylammonium chloride), polyacrylonitrile,poly(allylamine), poly(amide), poly(anhydride), poly(butylene),poly(ε-caprolactone), poly(carbonate), poly(ester),poly(etheretherketone), poly(ethersulphone), poly(ethylene),poly(ethylene alcohol), poly(ethylenimine), poly(ethylene glycol),poly(ethylene oxide), poly(glycolide) (like poly(glycolic acid)),poly(hydroxy butyrate), poly(hydroxyethylmethacrylate),poly(hydroxypropylmethacrylate), poly(hydroxystyrene), poly(imide),poly(lactide), poly(L-lactic acid) and poly(D,L-lactic acid)),poly(lactide-co-glycolide), poly(lysine), poly(methacrylate),poly(methylmethacrylate), poly(orthoester), poly(phenylene oxide),poly(phosphazene), poly(phosphoester), poly(propylene fumarate),poly(propylene), poly(propylene glycol), poly(propylene oxide),poly(styrene), poly(sulfone), poly(tetrafluoroethylene),poly(vinylacetate), poly(vinyl alcohol), poly(vinylchloride),poly(vinylidene fluoride), poly(vinyl pyrrolidone), poly(urethane), anycopolymer thereof (like poly(ethylene oxide)) poly(propylene oxide),copolymers (poloxamers), poly(vinyl alcohol-co-ethylene),poly(styrene-co-allyl) alcohol, and poly(ethylene)-block-poly(ethyleneglycol), and/or any mixtures thereof; as well as alginate, chitin,chitosan, collagen, dextran, gelatin, hyaluronic acid, pectin, and/ormixtures thereof. Methods for making porogens are well known in the artand non-limiting examples of such methods are described in, e.g., PeterX. Ma, Reverse Fabrication of Porous Materials, US 2002/00056000; P. X.Ma and G. Wei, Particle-Containing Complex Porous Materials, U.S.2006/0246121; and F. Liu, et al., Porogen Compositions, Methods ofMaking and Uses, U.S. 61/333,599; each of which is hereby incorporatedby reference in its entirety. Porogens are also commercially availablefrom, e.g., Polysciences Inc. (Warrington, Pa.).

Porogens have a shape sufficient to allow formation of a porogenscaffold useful in making a matrix as disclosed herein. Any porogenshape is useful with the proviso that the porogen shape is sufficient toallow formation of a porogen scaffold useful in making a matrix asdisclosed herein. Useful porogen shapes include, without limitation,roughly spherical, perfectly spherical, ellipsoidal, polyhedronal,triangular, pyramidal, quadrilateral like squares, rectangles,parallelograms, trapezoids, rhombus and kites, and other types ofpolygonal shapes.

In an embodiment, porogens have a shape sufficient to allow formation ofa porogen scaffold useful in making a matrix as disclosed herein. Inaspects of this embodiment, porogens have a shape that is roughlyspherical, perfectly spherical, ellipsoidal, polyhedronal, triangular,pyramidal, quadrilateral, or polygonal.

Porogens have a roundness sufficient to allow formation of a porogenscaffold useful in making a matrix as disclosed herein. As used herein,“roundness” is defined as (6×V)/(π×D³), where V is the volume and D isthe diameter. Any porogen roundness is useful with the proviso that theporogen roundness is sufficient to allow formation of a porogen scaffolduseful in making a matrix as disclosed herein.

In an embodiment, porogens has a roundness sufficient to allow formationof a porogen scaffold useful in making a matrix as disclosed herein. Inaspects of this embodiment, porogens have a mean roundness of, e.g.,about 0.1, about 0.2, about 0.3, about 0.4, about 0.5, about 0.6, about0.7, about 0.8, about 0.9, or about 1.0. In other aspects of thisembodiment, porogens have a mean roundness of, e.g., at least 0.1, atleast 0.2, at least 0.3, at least 0.4, at least 0.5, at least 0.6, atleast 0.7, at least 0.8, at least 0.9, or at least 1.0. In yet otheraspects of this embodiment, porogens have a mean roundness of, e.g., atmost 0.1, at most 0.2, at most 0.3, at most 0.4, at most 0.5, at most0.6, at most 0.7, at most 0.8, at most 0.9, or at most 1.0. In stillother aspects of this embodiment, porogens have a mean roundness of,e.g., about 0.1 to about 1.0, about 0.2 to about 1.0, about 0.3 to about1.0, about 0.4 to about 1.0, about 0.5 to about 1.0, about 0.6 to about1.0, about 0.7 to about 1.0, about 0.8 to about 1.0, about 0.9 to about1.0, about 0.1 to about 0.9, about 0.2 to about 0.9, about 0.3 to about0.9, about 0.4 to about 0.9, about 0.5 to about 0.9, about 0.6 to about0.9, about 0.7 to about 0.9, about 0.8 to about 0.9, about 0.1 to about0.8, about 0.2 to about 0.8, about 0.3 to about 0.8, about 0.4 to about0.8, about 0.5 to about 0.8, about 0.6 to about 0.8, about 0.7 to about0.8, about 0.1 to about 0.7, about 0.2 to about 0.7, about 0.3 to about0.7, about 0.4 to about 0.7, about 0.5 to about 0.7, about 0.6 to about0.7, about 0.1 to about 0.6, about 0.2 to about 0.6, about 0.3 to about0.6, about 0.4 to about 0.6, about 0.5 to about 0.6, about 0.1 to about0.5, about 0.2 to about 0.5, about 0.3 to about 0.5, or about 0.4 toabout 0.5.

The present specification discloses, in part, coating a matrix materialbase with porogens to form a matrix material-coated porogen mixture.Suitable matrix material bases are as described above. Coating theporogens with a matrix material base can be accomplished by any suitablemeans, including, without limitation, mechanical application such as,e.g., dipping, spraying, knifing, curtaining, brushing, or vapordeposition, thermal application, adhering application, chemical bonding,self-assembling, molecular entrapment, and/or any combination thereof.The matrix material base is applied to the porogens in such a manner asto coat the porogens with the desired thickness of the matrix material.Removal of excess matrix material can be accomplished by any suitablemeans, including, without limitation, gravity-based filtering orsieving, vacuum-based filtering or sieving, blowing, and/or anycombination thereof.

Thus, in an embodiment, porogens are coated with a matrix material baseto a thickness sufficient to enable the desired function of the porousmaterial. In aspects of this embodiment, porogens are coated with amatrix material base to a thickness of, e.g., about 1 μm, about 2 μm,about 3 μm, about 4 μm, about 5 μm, about 6 μm, about 7 μm, about 8 μm,about 9 μm, about 10 μm, about 20 μm, about 30 μm, about 40 μm, about 50μm, about 60 μm, about 70 μm, about 80 μm, about 90 μm, or about 100 μm.In other aspects of this embodiment, porogens are coated with a matrixmaterial base to a thickness of, e.g., at least 1 μm, at least 2 μm, atleast 3 μm, at least 4 μm, at least 5 μm, at least 6 μm, at least 7 μm,at least 8 μm, at least 9 μm, at least 10 μm, at least 20 μm, at least30 μm, at least 40 μm, at least 50 μm, at least 60 μm, at least 70 μm,at least 80 μm, at least 90 μm, or at least 100 μm. In yet other aspectsof this embodiment, porogens are coated with a matrix material base to athickness of, e.g., at most 1 μm, at most 2 μm, at most 3 μm, at most 4μm, at most 5 μm, at most 6 μm, at most 7 μm, at most 8 μm, at most 9μm, at most 10 μm, at most 20 μm, at most 30 μm, at most 40 μm, at most50 μm, at most 60 μm, at most 70 μm, at most 80 μm, at most 90 μm, or atmost 100 μm. In still other aspects of this embodiment, porogens arecoated with a matrix material base to a thickness of, e.g., about 1 μmto about 5 μm, about 1 μm to about 10 μm, about 5 μm to about 10 μm,about 5 μm to about 25 μm, about 5 μm to about 50 μm, about 10 μm toabout 50 μm, about 10 μm to about 75 μm, about 10 μm to about 100 μm,about 25 μm to about 100 μm, or about 50 μm to about 100 μm.

The present specification discloses, in part, devolitalizing a matrixmaterial-coated porogens. As used herein, the term “devolitalizing” or“devolitalization” refers to a process that removes volatile componentsfrom the matrix material-coated porogens. Devolitalization of the matrixmaterial-coated porogens can be accomplished by any suitable means thatremoves substantially all the volatile components from the matrixmaterial-coated porogens. Non-limiting examples of devolitalizingprocedures include evaporation, freeze-drying, sublimation, extraction,and/or any combination thereof.

In an embodiment, a matrix material-coated porogens is devolitalized ata single temperature for a time sufficient to allow the evaporation ofsubstantially all volatile components from the matrix material-coatedporogens. In an aspect of this embodiment, a matrix material-coatedporogens are devolitalized at ambient temperature for about 1 minute toabout 5 minutes. In another aspect of this embodiment, a matrixmaterial-coated porogens are devolitalized at ambient temperature forabout 45 minutes to about 75 minutes. In yet another aspect of thisembodiment, a matrix material-coated porogens are devolitalized atambient temperature for about 90 minutes to about 150 minutes. Inanother aspect of this embodiment, a matrix material-coated porogens aredevolitalized at about 18° C. to about 22° C. for about 1 minute toabout 5 minutes. In yet another aspect of this embodiment, a matrixmaterial-coated porogens are devolitalized at about 18° C. to about 22°C. for about 45 minutes to about 75 minutes. In still another aspect ofthis embodiment, a matrix material-coated porogens are devolitalized atabout 18° C. to about 22° C. for about 90 minutes to about 150 minutes.

The present specification discloses, in part, packing porogens into amold prior to fusion. Any mold shape may be used for packing theporogens. As a non-limiting example, a mold shape can be a shell thatoutlines the contours an implantable device, such as, e.g., a shell fora breast implant, or a shell for a muscle implant. As anothernon-limiting example, the mold shape can be one that forms sheets. Suchsheets can be made in a wide variety or proportions based on the neededapplication. For example, the sheets can be made in a size slightlybigger that an implantable medical device so that there is sufficientmaterial to cover the device and allow for trimming of the excess. Asanother example, the sheets can be produced as a continuous roll thatallows a person skilled in the art to take only the desired amount foran application, such as, e.g., creating strips having a textured surfacefor control of scar formation. As yet another non-limiting example, amold shape can be a three-dimensional form that represents the finalshape of the porous material, such as, e.g., a filter, an insulatingmaterial, a light armor panel. The porogens may be packed into a moldusing ultrasonic agitation, mechanical agitation, or any other suitablemethod for obtaining a closely packed array of porogens.

In an embodiment, a matrix material-coated porogen mixture is packedinto a mold. In an aspect of this embodiment, a matrix material-coatedporogen mixture is packed into a mold in a manner suitable obtaining aclosely packed array of porogens. In other aspects of this embodiment, amatrix material-coated porogen mixture is packed into a mold using sonicagitation or mechanical agitation.

The present specification discloses, in part, treating a matrixmaterial-coated porogen mixture to allow fusing of the porogens to forma porogen scaffold and curing or hardening of the matrix material base.As used herein, the term “treating” refers to a process that 1) fusesthe porogens to form a porogen scaffold useful to make a matrix asdisclosed herein and 2) cures the matrix material base (e.g., athermoset, an elastomer, a thermoplastic elastomer) to form a matrixcomprising an array of interconnected of pores as disclosed herein; orhardens the matrix material base (e.g., a thermoplastic) to form amatrix comprising an array of interconnected of pores as disclosedherein. As used herein, the term “curing” is synonymous with “setting”or “vulcanizing” and refers to an irreversible process that exposes thechains of a polymer to a element which activates a phase change in thepolymer to a more stable state, such as, e.g., by physically orchemically cross-linked polymer chains to one another. As used herein,the term “hardening” refers to a reversible process where the matrixmaterial transitions from a fluid state to a solid state, as typifiedfor a thermoplastic. Non-limiting examples of treating include thermaltreating, chemical treating, catalyst treating, radiation treating, andphysical treating. Treating of a matrix material-coated porogen scaffoldcan be done under any condition for any length of time with the provisothat the treating fuses the porogens to form a porogen scaffold usefulto make a matrix as disclosed herein and cures or hardens the matrixmaterial.

Thermal treating a matrix material-coated porogen mixture can be at anytemperature or temperatures for any length of time or times with theproviso that the thermal treatment fuses the porogens to form a porogenscaffold and cures or hardens the matrix material base. A non-limitingexample of temperatures useful in a thermal treatment are temperatureshigher than the glass transition temperature or melting temperature ofthe porogens, such as between about 5° C. to about 50° C. higher thanthe glass transition temperature or melting temperature of the porogens.Any temperature can be used in a thermal treatment with the proviso thatthe temperature is sufficient to cause fusion of the porogens. As anon-limiting example, the thermal treatment can be from about 30° C. toabout 250° C. Increasing the duration of the thermal treatment at agiven temperature increases the connection size; increases the sinteringtemperature, and increases the growth rate of the connections. Any timecan be used in a thermal treatment with the proviso that the time issufficient to cause fusion of the porogens and cures or hardens thematrix material base. Suitable times are generally from about 0.5 hoursto about 48 hours.

Thus, in an embodiment, matrix material-coated porogens are treated bythermal treatment, chemical treatment, catalyst treatment, radiationtreatment, or physical treatment. In another embodiment, matrixmaterial-coated porogens are treated at a single time, where the curingtime is sufficient to form a matrix comprising an array ofinterconnected of pores as disclosed herein.

In another embodiment, matrix material-coated porogens are thermaltreated at a single temperature for a single time, where the treatingtemperature and time is sufficient to fuse the porogens to form aporogen scaffold and cure or harden the matrix material base.

In other aspects of this embodiment, a thermal treatment comprisesheating a matrix material-coated porogens for a time at, e.g., about 5°C. higher, about 10° C. higher, about 15° C. higher, about 20° C.higher, about 25° C. higher, about 30° C. higher, about 35° C. higher,about 40° C. higher, about 45° C. higher, or about 50° C. higher thanthe melting temperature or glass transition temperature of the porogens,where the treating temperature and time is sufficient to fuse theporogens to form a porogen scaffold and cure or harden the matrixmaterial base. In yet other aspects of this embodiment, a thermaltreatment comprises heating a matrix material-coated porogens for a timeat, e.g., at least 5° C. higher, at least 10° C. higher, at least 15° C.higher, at least 20° C. higher, at least 25° C. higher, at least 30° C.higher, at least 35° C. higher, at least 40° C. higher, at least 45° C.higher, or at least 50° C. higher than the melting temperature or glasstransition temperature of the porogens, where the treating temperatureand time is sufficient to fuse the porogens to form a porogen scaffoldand cure or harden the matrix material base. In still other aspects ofthis embodiment, a thermal treatment comprises heating a matrixmaterial-coated porogens for a time at, e.g., at most 5° C. higher, atmost 10° C. higher, at most 15° C. higher, at most 20° C. higher, atmost 25° C. higher, at most 30° C. higher, at most 35° C. higher, atmost 40° C. higher, at most 45° C. higher, or at most 50° C. higher thanthe melting temperature or glass transition temperature of the porogens,where the treating temperature and time is sufficient to fuse theporogens to form a porogen scaffold and cure or harden the matrixmaterial base. In further aspects of this embodiment, a thermaltreatment comprises heating a matrix material-coated porogens for a timeat, e.g., about 5° C. higher to about 10° C. higher, about 5° C. higherto about 15° C. higher, about 5° C. higher to about 20° C. higher, about5° C. higher to about 25° C. higher, about 5° C. higher to about 30° C.higher, about 5° C. higher to about 35° C. higher, about 5° C. higher toabout 40° C. higher, about 5° C. higher to about 45° C. higher, about 5°C. higher to about 50° C. higher, about 10° C. higher to about 15° C.higher, about 10° C. higher to about 20° C. higher, about 10° C. higherto about 25° C. higher, about 10° C. higher to about 30° C. higher,about 10° C. higher to about 35° C. higher, about 10° C. higher to about40° C. higher, about 10° C. higher to about 45° C. higher, or about 10°C. higher to about 50° C. higher than the melting temperature or glasstransition temperature of the porogens, where the treating temperatureand time is sufficient to fuse the porogens to form a porogen scaffoldand cure or harden the matrix material base.

In another aspect of this embodiment, the thermal treatment comprisesheating a matrix material-coated porogen scaffold is treated at about30° C. to about 130° C. for about 10 minutes to about 360 minutes, wherethe treating temperature and time is sufficient to fuse the porogens toform a porogen scaffold and cure or harden the matrix material base.

In yet another embodiment, a matrix material-coated porogens are thermaltreated at a plurality of temperatures for a plurality of times, wherethe treating temperatures and times are sufficient to fuse the porogensto form a porogen scaffold and cure or harden the matrix material base.In an aspect of this embodiment, matrix material-coated porogens aretreated at a first temperature for a first time, and then a secondtemperature for a second time, where the treating temperatures and timesare sufficient to fuse the porogens to form a porogen scaffold and cureor harden the matrix material base, and where the first and secondtemperatures are different.

In aspects of this embodiment, thermal treatment comprises heating thematrix material-coated porogens at a first temperature for a first time,and then heating the porogens at a second temperature for a second time,where the treating temperatures and times are sufficient to fuse theporogens to form a porogen scaffold and cure or harden the matrixmaterial base, and where the first and second temperatures aredifferent. In other aspects of this embodiment, a thermal treatmentcomprises heating a matrix material-coated porogens for a first time at,e.g., about 5° C. higher, about 10° C. higher, about 15° C. higher,about 20° C. higher, about 25° C. higher, about 30° C. higher, about 35°C. higher, about 40° C. higher, about 45° C. higher, or about 50° C.higher than the melting temperature or glass transition temperature ofthe matrix material-coated porogens, then heating for a second time theporogens at, e.g., about 5° C. higher, about 10° C. higher, about 15° C.higher, about 20° C. higher, about 25° C. higher, about 30° C. higher,about 35° C. higher, about 40° C. higher, about 45° C. higher, or about50° C. higher than the melting temperature or glass transitiontemperature of the porogens, where the treating temperatures and timesare sufficient to fuse the porogens to form a porogen scaffold and cureor harden the matrix material base, and where the first and secondtemperatures are different. In yet other aspects of this embodiment, athermal treatment comprises heating a matrix material-coated porogensfor a first time at, e.g., at least 5° C. higher, at least 10° C.higher, at least 15° C. higher, at least 20° C. higher, at least 25° C.higher, at least 30° C. higher, at least 35° C. higher, at least 40° C.higher, at least 45° C. higher, or at least 50° C. higher than themelting temperature or glass transition temperature of the porogens,then heating the matrix material-coated porogens for a second time at,e.g., at least 5° C. higher, at least 10° C. higher, at least 15° C.higher, at least 20° C. higher, at least 25° C. higher, at least 30° C.higher, at least 35° C. higher, at least 40° C. higher, at least 45° C.higher, or at least 50° C. higher than the melting temperature or glasstransition temperature of the porogens, where the treating temperaturesand times are sufficient to fuse the porogens to form a porogen scaffoldand cure or harden the matrix material base, and where the first andsecond temperatures are different. In still other aspects of thisembodiment, a thermal treatment comprises heating a matrixmaterial-coated porogens for a first time at, e.g., at most 5° C.higher, at most 10° C. higher, at most 15° C. higher, at most 20° C.higher, at most 25° C. higher, at most 30° C. higher, at most 35° C.higher, at most 40° C. higher, at most 45° C. higher, or at most 50° C.higher than the melting temperature or glass transition temperature ofthe porogens, then heating the matrix material-coated porogens for asecond time at, e.g., at most 5° C. higher, at most 10° C. higher, atmost 15° C. higher, at most 20° C. higher, at most 25° C. higher, atmost 30° C. higher, at most 35° C. higher, at most 40° C. higher, atmost 45° C. higher, or at most 50° C. higher than the meltingtemperature or glass transition temperature of the porogens, where thetreating temperatures and times are sufficient to fuse the porogens toform a porogen scaffold and cure or harden the matrix material base, andwhere the first and second temperatures are different.

In further aspects of this embodiment, a thermal treatment comprisesheating a matrix material-coated porogens for a first time at, e.g.,about 5° C. higher to about 10° C. higher, about 5° C. higher to about15° C. higher, about 5° C. higher to about 20° C. higher, about 5° C.higher to about 25° C. higher, about 5° C. higher to about 30° C.higher, about 5° C. higher to about 35° C. higher, about 5° C. higher toabout 40° C. higher, about 5° C. higher to about 45° C. higher, about 5°C. higher to about 50° C. higher, about 10° C. higher to about 15° C.higher, about 10° C. higher to about 20° C. higher, about 10° C. higherto about 25° C. higher, about 10° C. higher to about 30° C. higher,about 10° C. higher to about 35° C. higher, about 10° C. higher to about40° C. higher, about 10° C. higher to about 45° C. higher, or about 10°C. higher to about 50° C. higher than the melting temperature or glasstransition temperature of the porogens, then heating the matrixmaterial-coated porogens for a second time at, e.g., about 5° C. higherto about 10° C. higher, about 5° C. higher to about 15° C. higher, about5° C. higher to about 20° C. higher, about 5° C. higher to about 25° C.higher, about 5° C. higher to about 30° C. higher, about 5° C. higher toabout 35° C. higher, about 5° C. higher to about 40° C. higher, about 5°C. higher to about 45° C. higher, about 5° C. higher to about 50° C.higher, about 10° C. higher to about 15° C. higher, about 10° C. higherto about 20° C. higher, about 10° C. higher to about 25° C. higher,about 10° C. higher to about 30° C. higher, about 10° C. higher to about35° C. higher, about 10° C. higher to about 40° C. higher, about 10° C.higher to about 45° C. higher, or about 10° C. higher to about 50° C.higher than the melting temperature or glass transition temperature ofthe porogens, where the treating temperatures and times are sufficientto fuse the porogens to form a porogen scaffold and cure or harden thematrix material base, and where the first and second temperatures aredifferent.

In other aspects of this embodiment, thermal treatment comprises heatingthe matrix material-coated porogens at a first temperature for a firsttime, heating the porogens at a second temperature for a second time,and then heating the porogens at a third temperature at a third time,where the treating temperatures and times are sufficient to fuse theporogens to form a porogen scaffold and cure or harden the matrixmaterial base, and where the first temperature is different from thesecond temperature and the second temperature is different from thethird temperature.

In other aspects of this embodiment, a thermal treatment comprisesheating a matrix material-coated porogens for a first time at, e.g.,about 5° C. higher, about 10° C. higher, about 15° C. higher, about 20°C. higher, about 25° C. higher, about 30° C. higher, about 35° C.higher, about 40° C. higher, about 45° C. higher, or about 50° C. higherthan the melting temperature or glass transition temperature of theporogens, then heating the matrix material-coated porogens for a secondtime at, e.g., about 5° C. higher, about 10° C. higher, about 15° C.higher, about 20° C. higher, about 25° C. higher, about 30° C. higher,about 35° C. higher, about 40° C. higher, about 45° C. higher, or about50° C. higher than the melting temperature or glass transitiontemperature of the porogens, then heating the matrix material-coatedporogens for a third time at, e.g., about 5° C. higher, about 10° C.higher, about 15° C. higher, about 20° C. higher, about 25° C. higher,about 30° C. higher, about 35° C. higher, about 40° C. higher, about 45°C. higher, or about 50° C. higher than the melting temperature or glasstransition temperature of the porogens, where the treating temperaturesand times are sufficient to fuse the porogens to form a porogen scaffoldand cure or harden the matrix material base, and where the firsttemperature is different from the second temperature and the secondtemperature is different from the third temperature. In yet otheraspects of this embodiment, a thermal treatment comprises heating amatrix material-coated porogens for a first time at, e.g., at least 5°C. higher, at least 10° C. higher, at least 15° C. higher, at least 20°C. higher, at least 25° C. higher, at least 30° C. higher, at least 35°C. higher, at least 40° C. higher, at least 45° C. higher, or at least50° C. higher than the melting temperature or glass transitiontemperature of the porogens, then heating the matrix material-coatedporogens for a second time at, e.g., at least 5° C. higher, at least 10°C. higher, at least 15° C. higher, at least 20° C. higher, at least 25°C. higher, at least 30° C. higher, at least 35° C. higher, at least 40°C. higher, at least 45° C. higher, or at least 50° C. higher than themelting temperature or glass transition temperature of the porogens,then heating the matrix material-coated porogens for a third time at,e.g., at least 5° C. higher, at least 10° C. higher, at least 15° C.higher, at least 20° C. higher, at least 25° C. higher, at least 30° C.higher, at least 35° C. higher, at least 40° C. higher, at least 45° C.higher, or at least 50° C. higher than the melting temperature or glasstransition temperature of the porogens, where the treating temperaturesand times are sufficient to fuse the porogens to form a porogen scaffoldand cure or harden the matrix material base, and where the firsttemperature is different from the second temperature and the secondtemperature is different from the third temperature. In still otheraspects of this embodiment, a thermal treatment comprises heating amatrix material-coated porogens for a first time at, e.g., at most 5° C.higher, at most 10° C. higher, at most 15° C. higher, at most 20° C.higher, at most 25° C. higher, at most 30° C. higher, at most 35° C.higher, at most 40° C. higher, at most 45° C. higher, or at most 50° C.higher than the melting temperature or glass transition temperature ofthe porogens, then heating the matrix material-coated porogens for asecond time at, e.g., at most 5° C. higher, at most 10° C. higher, atmost 15° C. higher, at most 20° C. higher, at most 25° C. higher, atmost 30° C. higher, at most 35° C. higher, at most 40° C. higher, atmost 45° C. higher, or at most 50° C. higher than the meltingtemperature or glass transition temperature of the porogens, thenheating the matrix material-coated porogens for a third time at, e.g.,at most 5° C. higher, at most 10° C. higher, at most 15° C. higher, atmost 20° C. higher, at most 25° C. higher, at most 30° C. higher, atmost 35° C. higher, at most 40° C. higher, at most 45° C. higher, or atmost 50° C. higher than the melting temperature or glass transitiontemperature of the porogens, where the treating temperatures and timesare sufficient to fuse the porogens to form a porogen scaffold and cureor harden the matrix material base, and where the first temperature isdifferent from the second temperature and the second temperature isdifferent from the third temperature.

In further aspects of this embodiment, a thermal treatment comprisesheating a matrix material-coated porogens for a first time at, e.g.,about 5° C. higher to about 10° C. higher, about 5° C. higher to about15° C. higher, about 5° C. higher to about 20° C. higher, about 5° C.higher to about 25° C. higher, about 5° C. higher to about 30° C.higher, about 5° C. higher to about 35° C. higher, about 5° C. higher toabout 40° C. higher, about 5° C. higher to about 45° C. higher, about 5°C. higher to about 50° C. higher, about 10° C. higher to about 15° C.higher, about 10° C. higher to about 20° C. higher, about 10° C. higherto about 25° C. higher, about 10° C. higher to about 30° C. higher,about 10° C. higher to about 35° C. higher, about 10° C. higher to about40° C. higher, about 10° C. higher to about 45° C. higher, or about 10°C. higher to about 50° C. higher than the melting temperature or glasstransition temperature of the porogens, then heating the matrixmaterial-coated porogens for a second time at, e.g., about 5° C. higherto about 10° C. higher, about 5° C. higher to about 15° C. higher, about5° C. higher to about 20° C. higher, about 5° C. higher to about 25° C.higher, about 5° C. higher to about 30° C. higher, about 5° C. higher toabout 35° C. higher, about 5° C. higher to about 40° C. higher, about 5°C. higher to about 45° C. higher, about 5° C. higher to about 50° C.higher, about 10° C. higher to about 15° C. higher, about 10° C. higherto about 20° C. higher, about 10° C. higher to about 25° C. higher,about 10° C. higher to about 30° C. higher, about 10° C. higher to about35° C. higher, about 10° C. higher to about 40° C. higher, about 10° C.higher to about 45° C. higher, or about 10° C. higher to about 50° C.higher than the melting temperature or glass transition temperature ofthe porogens, then heating the matrix material-coated porogens for athird time at, e.g., about 5° C. higher to about 10° C. higher, about 5°C. higher to about 15° C. higher, about 5° C. higher to about 20° C.higher, about 5° C. higher to about 25° C. higher, about 5° C. higher toabout 30° C. higher, about 5° C. higher to about 35° C. higher, about 5°C. higher to about 40° C. higher, about 5° C. higher to about 45° C.higher, about 5° C. higher to about 50° C. higher, about 10° C. higherto about 15° C. higher, about 10° C. higher to about 20° C. higher,about 10° C. higher to about 25° C. higher, about 10° C. higher to about30° C. higher, about 10° C. higher to about 35° C. higher, about 10° C.higher to about 40° C. higher, about 10° C. higher to about 45° C.higher, or about 10° C. higher to about 50° C. higher than the meltingtemperature or glass transition temperature of the porogens, where thetreating temperatures and times are sufficient to fuse the porogens toform a porogen scaffold and cure or harden the matrix material base, andwhere the first temperature is different from the second temperature andthe second temperature is different from the third temperature.

In still other aspect of this embodiment, matrix material-coatedporogens are treated at about 60° C. to about 75° C. for about 15minutes to about 45 minutes, and then at about 120° C. to about 130° C.for about 60 minutes to about 90 minutes, where the treatingtemperatures and times is sufficient to fuse the porogens to form aporogen scaffold and cure or harden the matrix material base. In afurther aspect of this embodiment, matrix material-coated porogenmixture is treated at about 60° to about 75° C. for about 15 minutes toabout 45 minutes, then at about 135° C. to about 150° C. for about 90minutes to about 150 minutes, and then at about 150° C. to about 165° C.for about 15 minutes to about 45 minutes.

The present specification discloses, in part, to form a porogenscaffold. As used herein, the term “porogen scaffold” refers to athree-dimensional structural framework composed of fused porogens thatserves as the negative replica of the matrix defining an interconnectedarray or pores as disclosed herein.

The porogen scaffold is formed in such a manner that substantially allthe fused porogens in the porogen scaffold have a similar diameter. Asused herein, the term “substantially”, when used to describe fusedporogen, refers to at least 90% of the porogen comprising the porogenscaffold are fused, such as, e.g., at least 95% of the porogens arefused or at least 97% of the porogen are fused. As used herein, the term“similar diameter”, when used to describe fused porogen, refers to adifference in the diameters of the two fused porogen that is less thanabout 20% of the larger diameter. As used herein, the term “diameter”,when used to describe fused porogen, refers to the longest line segmentthat can be drawn that connects two points within the fused porogen,regardless of whether the line passes outside the boundary of the fusedporogen. Any fused porogen diameter is useful with the proviso that thefused porogen diameter is sufficient to allow formation of a porogenscaffold useful in making a matrix as disclosed herein.

The porogen scaffold is formed in such a manner that the diameter of theconnections between each fused porogen is sufficient to allow formationof a porogen scaffold useful in making a matrix as disclosed herein. Asused herein, the term “diameter”, when describing the connection betweenfused porogens, refers to the diameter of the cross-section of theconnection between two fused porogens in the plane normal to the lineconnecting the centroids of the two fused porogens, where the plane ischosen so that the area of the cross-section of the connection is at itsminimum value. As used herein, the term “diameter of a cross-section ofa connection” refers to the average length of a straight-line segmentthat passes through the center, or centroid (in the case of a connectionhaving a cross-section that lacks a center), of the cross-section of aconnection and terminates at the periphery of the cross-section. As usedherein, the term “substantially”, when used to describe the connectionsbetween fused porogens refers to at least 90% of the fused porogenscomprising the porogen scaffold make connections between each other,such as, e.g., at least 95% of the fused porogens make connectionsbetween each other or at least 97% of the fused porogens makeconnections between each other.

In an embodiment, a porogen scaffold comprises fused porogens wheresubstantially all the fused porogens have a similar diameter. In aspectsof this embodiment, at least 90% of all the fused porogens have asimilar diameter, at least 95% of all the fused porogens have a similardiameter, or at least 97% of all the fused porogens have a similardiameter. In another aspect of this embodiment, difference in thediameters of two fused porogens is, e.g., less than about 20% of thelarger diameter, less than about 15% of the larger diameter, less thanabout 10% of the larger diameter, or less than about 5% of the largerdiameter.

In another embodiment, a porogen scaffold comprises fused porogens havea mean diameter sufficient to enable the desired function of the porousmaterial. In aspects of this embodiment, a porogen scaffold comprisesfused porogens comprising mean fused porogen diameter of, e.g., about 50μm, about 75 μm, about 100 μm, about 150 μm, about 200 μm, about 250 μm,about 300 μm, about 350 μm, about 400 μm, about 450 μm, or about 500 μm.In other aspects, a porogen scaffold comprises fused porogens comprisingmean fused porogen diameter of, e.g., about 500 μm, about 600 μm, about700 μm, about 800 μm, about 900 μm, about 1000 μm, about 1500 μm, about2000 μm, about 2500 μm, or about 3000 μm. In yet other aspects of thisembodiment, a porogen scaffold comprises fused porogens comprising meanfused porogen diameter of, e.g., at least 50 μm, at least 75 μm, atleast 100 μm, at least 150 μm, at least 200 μm, at least 250 μm, atleast 300 μm, at least 350 μm, at least 400 μm, at least 450 μm, or atleast 500 μm. In still other aspects, a matrix comprises fused porogenscomprising mean fused porogen diameter of, e.g., at least 500 μm, atleast 600 μm, at least 700 μm, at least 800 μm, at least 900 μm, atleast 1000 μm, at least 1500 μm, at least 2000 μm, at least 2500 μm, orat least 3000 μm. In further aspects of this embodiment, a porogenscaffold comprises fused porogens comprising mean fused porogen diameterof, e.g., at most 50 μm, at most 75 μm, at most 100 μm, at most 150 μm,at most 200 μm, at most 250 μm, at most 300 μm, at most 350 μm, at most400 μm, at most 450 μm, or at most 500 μm. In yet further aspects ofthis embodiment, a matrix comprises fused porogens comprising mean fusedporogen diameter of, e.g., at most 500 μm, at most 600 μm, at most 700μm, at most 800 μm, at most 900 μm, at most 1000 μm, at most 1500 μm, atmost 2000 μm, at most 2500 μm, or at most 3000 μm. In still furtheraspects of this embodiment, a porogen scaffold comprises fused porogenscomprising mean fused porogen diameter in a range from, e.g., about 300μm to about 600 μm, about 200 μm to about 700 μm, about 100 μm to about800 μm, about 500 μm to about 800 μm, about 50 μm to about 500 μm, about75 μm to about 500 μm, about 100 μm to about 500 μm, about 200 μm toabout 500 μm, about 300 μm to about 500 μm, about 50 μm to about 1000μm, about 75 μm to about 1000 μm, about 100 μm to about 1000 μm, about200 μm to about 1000 μm, about 300 μm to about 1000 μm, about 50 μm toabout 1000 μm, about 75 μm to about 3000 μm, about 100 μm to about 3000μm, about 200 μm to about 3000 μm, or about 300 μm to about 3000 μm.

In another embodiment, a porogen scaffold comprises fused porogensconnected to a plurality of other porogens. In aspects of thisembodiment, a porogen scaffold comprises a mean fused porogenconnectivity, e.g., about two other fused porogens, about three otherfused porogens, about four other fused porogens, about five other fusedporogens, about six other fused porogens, about seven other fusedporogens, about eight other fused porogens, about nine other fusedporogens, about ten other fused porogens, about 11 other fused porogens,or about 12 other fused porogens. In other aspects of this embodiment, aporogen scaffold comprises a mean fused porogen connectivity, e.g., atleast two other fused porogens, at least three other fused porogens, atleast four other fused porogens, at least five other fused porogens, atleast six other fused porogens, at least seven other fused porogens, atleast eight other fused porogens, at least nine other fused porogens, atleast ten other fused porogens, at least 11 other fused porogens, or atleast 12 other fused porogens. In yet other aspects of this embodiment,a porogen scaffold comprises a mean fused porogen connectivity, e.g., atmost two other fused porogens, at most three other fused porogens, atmost four other fused porogens, at most five other fused porogens, atmost six other fused porogens, at most seven other fused porogens, atmost eight other fused porogens, at most nine other fused porogens, atmost ten other fused porogens, at most 11 other fused porogens, or atmost 12 other fused porogens.

In still other aspects of this embodiment, a porogen scaffold comprisesfused porogens connected to, e.g., about two other fused porogens toabout 12 other fused porogens, about two other fused porogens to about11 other fused porogens, about two other fused porogens to about tenother fused porogens, about two other fused porogens to about nine otherfused porogens, about two other fused porogens to about eight otherfused porogens, about two other fused porogens to about seven otherfused porogens, about two other fused porogens to about six other fusedporogens, about two other fused porogens to about five other fusedporogens, about three other fused porogens to about 12 other fusedporogens, about three other fused porogens to about 11 other fusedporogens, about three other fused porogens to about ten other fusedporogens, about three other fused porogens to about nine other fusedporogens, about three other fused porogens to about eight other fusedporogens, about three other fused porogens to about seven other fusedporogens, about three other fused porogens to about six other fusedporogens, about three other fused porogens to about five other fusedporogens, about four other fused porogens to about 12 other fusedporogens, about four other fused porogens to about 11 other fusedporogens, about four other fused porogens to about ten other fusedporogens, about four other fused porogens to about nine other fusedporogens, about four other fused porogens to about eight other fusedporogens, about four other fused porogens to about seven other fusedporogens, about four other fused porogens to about six other fusedporogens, about four other fused porogens to about five other fusedporogens, about five other fused porogens to about 12 other fusedporogens, about five other fused porogens to about 11 other fusedporogens, about five other fused porogens to about ten other fusedporogens, about five other fused porogens to about nine other fusedporogens, about five other fused porogens to about eight other fusedporogens, about five other fused porogens to about seven other fusedporogens, or about five other fused porogens to about six other fusedporogens.

In another embodiment, a porogen scaffold comprises fused porogens wherethe diameter of the connections between the fused porogens is sufficientto enable the desired function of the porous material. In aspects ofthis embodiment, the porogen scaffold comprises fused porogens where thediameter of the connections between the fused porogens is, e.g., about10% the mean fused porogen diameter, about 20% the mean fused porogendiameter, about 30% the mean fused porogen diameter, about 40% the meanfused porogen diameter, about 50% the mean fused porogen diameter, about60% the mean fused porogen diameter, about 70% the mean fused porogendiameter, about 80% the mean fused porogen diameter, or about 90% themean fused porogen diameter. In other aspects of this embodiment, theporogen scaffold comprises fused porogens where the diameter of theconnections between the fused porogens is, e.g., at least 10% the meanfused porogen diameter, at least 20% the mean fused porogen diameter, atleast 30% the mean fused porogen diameter, at least 40% the mean fusedporogen diameter, at least 50% the mean fused porogen diameter, at least60% the mean fused porogen diameter, at least 70% the mean fused porogendiameter, at least 80% the mean fused porogen diameter, or at least 90%the mean fused porogen diameter. In yet other aspects of thisembodiment, the porogen scaffold comprises fused porogens where thediameter of the connections between the fused porogens is, e.g., at most10% the mean fused porogen diameter, at most 20% the mean fused porogendiameter, at most 30% the mean fused porogen diameter, at most 40% themean fused porogen diameter, at most 50% the mean fused porogendiameter, at most 60% the mean fused porogen diameter, at most 70% themean fused porogen diameter, at most 80% the mean fused porogendiameter, or at most 90% the mean fused porogen diameter.

In still other aspects of this embodiment, a porogen scaffold comprisesfused porogens where the diameter of the connections between the fusedporogens is, e.g., about 10% to about 90% the mean fused porogendiameter, about 15% to about 90% the mean fused porogen diameter, about20% to about 90% the mean fused porogen diameter, about 25% to about 90%the mean fused porogen diameter, about 30% to about 90% the mean fusedporogen diameter, about 35% to about 90% the mean fused porogendiameter, about 40% to about 90% the mean fused porogen diameter, about10% to about 80% the mean fused porogen diameter, about 15% to about 80%the mean fused porogen diameter, about 20% to about 80% the mean fusedporogen diameter, about 25% to about 80% the mean fused porogendiameter, about 30% to about 80% the mean fused porogen diameter, about35% to about 80% the mean fused porogen diameter, about 40% to about 80%the mean fused porogen diameter, about 10% to about 70% the mean fusedporogen diameter, about 15% to about 70% the mean fused porogendiameter, about 20% to about 70% the mean fused porogen diameter, about25% to about 70% the mean fused porogen diameter, about 30% to about 70%the mean fused porogen diameter, about 35% to about 70% the mean fusedporogen diameter, about 40% to about 70% the mean fused porogendiameter, about 10% to about 60% the mean fused porogen diameter, about15% to about 60% the mean fused porogen diameter, about 20% to about 60%the mean fused porogen diameter, about 25% to about 60% the mean fusedporogen diameter, about 30% to about 60% the mean fused porogendiameter, about 35% to about 60% the mean fused porogen diameter, about40% to about 60% the mean fused porogen diameter, about 10% to about 50%the mean fused porogen diameter, about 15% to about 50% the mean fusedporogen diameter, about 20% to about 50% the mean fused porogendiameter, about 25% to about 50% the mean fused porogen diameter, about30% to about 50% the mean fused porogen diameter, about 10% to about 40%the mean fused porogen diameter, about 15% to about 40% the mean fusedporogen diameter, about 20% to about 40% the mean fused porogendiameter, about 25% to about 40% the mean fused porogen diameter, orabout 30% to about 40% the mean fused porogen diameter.

The present specification discloses, in part, removing a porogenscaffold from a cured or hardened matrix material. Removal of theporogen scaffold can be accomplished by any suitable means, with theproviso that the resulting porous material comprises a matrix definingan array of interconnected pores useful for its intended purpose.Non-limiting examples of porogen removal include solvent extraction,thermal decomposition extraction, degradation extraction, mechanicalextraction, and/or any combination thereof. The resulting porousmaterial comprising a matrix defining an array of interconnected poresis as described herein. In extraction methods requiring exposure toanother solution, such as, e.g., solvent extraction, the extraction canincorporate a plurality of solution changes over time to facilitateremoval of the porogen scaffold. Non-limiting examples of solventsuseful for solvent extraction include water, methylene chloride, aceticacid, formic acid, pyridine, tetrahydrofuran, dimethylsulfoxide,dioxane, benzene, and/or mixtures thereof. A mixed solvent can be in aratio of higher than about 1:1, first solvent to second solvent or lowerthan about 1:1, first solvent to second solvent.

In an embodiment, a porogen scaffold is removed by extraction, where theextraction removes substantially all the porogen scaffold leaving amatrix defining an array of interconnected pores. In aspects of thisembodiment, a porogen scaffold is removed by extraction, where theextraction removes, e.g., about 75% of the porogen scaffold, about 80%of the porogen scaffold, about 85% of the porogen scaffold, about 90% ofthe porogen scaffold, or about 95% of the porogen scaffold. In otheraspects of this embodiment, a porogen scaffold is removed by extraction,where the extraction removes, e.g., at least 75% of the porogenscaffold, at least 80% of the porogen scaffold, at least 85% of theporogen scaffold, at least 90% of the porogen scaffold, or at least 95%of the porogen scaffold. In aspects of this embodiment, a porogenscaffold is removed by extraction, where the extraction removes, e.g.,about 75% to about 90% of the porogen scaffold, about 75% to about 95%of the porogen scaffold, about 75% to about 100% of the porogenscaffold, about 80% to about 90% of the porogen scaffold, about 80% toabout 95% of the porogen scaffold, about 80% to about 100% of theporogen scaffold, about 85% to about 90% of the porogen scaffold, about85% to about 95% of the porogen scaffold, or about 85% to about 100% ofthe porogen scaffold. In an aspect, a porogen scaffold is removed by asolvent extraction, a thermal decomposition extraction, a degradationextraction, a mechanical extraction, and/or any combination thereof.

In another embodiment, a porogen scaffold is removed by solventextraction, where the extraction removes substantially all the porogenscaffold leaving a matrix defining an array of interconnected pores. Inaspects of this embodiment, a porogen scaffold is removed by solventextraction, where the extraction removes, e.g., about 75% of the porogenscaffold, about 80% of the porogen scaffold, about 85% of the porogenscaffold, about 90% of the porogen scaffold, or about 95% of the porogenscaffold. In other aspects of this embodiment, a porogen scaffold isremoved by solvent extraction, where the extraction removes, e.g., atleast 75% of the porogen scaffold, at least 80% of the porogen scaffold,at least 85% of the porogen scaffold, at least 90% of the porogenscaffold, or at least 95% of the porogen scaffold. In aspects of thisembodiment, a porogen scaffold is removed by solvent extraction, wherethe extraction removes, e.g., about 75% to about 90% of the porogenscaffold, about 75% to about 95% of the porogen scaffold, about 75% toabout 100% of the porogen scaffold, about 80% to about 90% of theporogen scaffold, about 80% to about 95% of the porogen scaffold, about80% to about 100% of the porogen scaffold, about 85% to about 90% of theporogen scaffold, about 85% to about 95% of the porogen scaffold, orabout 85% to about 100% of the porogen scaffold.

In yet another embodiment, a porogen scaffold is removed by thermaldecomposition extraction, where the extraction removes substantially allthe porogen scaffold leaving a matrix defining an array ofinterconnected pores. In aspects of this embodiment, a porogen scaffoldis removed by thermal extraction, where the extraction removes, e.g.,about 75% of the porogen scaffold, about 80% of the porogen scaffold,about 85% of the porogen scaffold, about 90% of the porogen scaffold, orabout 95% of the porogen scaffold. In other aspects of this embodiment,a porogen scaffold is removed by thermal extraction, where theextraction removes, e.g., at least 75% of the porogen scaffold, at least80% of the porogen scaffold, at least 85% of the porogen scaffold, atleast 90% of the porogen scaffold, or at least 95% of the porogenscaffold. In aspects of this embodiment, a porogen scaffold is removedby thermal extraction, where the extraction removes, e.g., about 75% toabout 90% of the porogen scaffold, about 75% to about 95% of the porogenscaffold, about 75% to about 100% of the porogen scaffold, about 80% toabout 90% of the porogen scaffold, about 80% to about 95% of the porogenscaffold, about 80% to about 100% of the porogen scaffold, about 85% toabout 90% of the porogen scaffold, about 85% to about 95% of the porogenscaffold, or about 85% to about 100% of the porogen scaffold.

In still another embodiment, a porogen scaffold is removed bydegradation extraction, where the extraction removes substantially allthe porogen scaffold leaving a matrix defining an array ofinterconnected pores. In aspects of this embodiment, a porogen scaffoldis removed by degradation extraction, where the extraction removes,e.g., about 75% of the porogen scaffold, about 80% of the porogenscaffold, about 85% of the porogen scaffold, about 90% of the porogenscaffold, or about 95% of the porogen scaffold. In other aspects of thisembodiment, a porogen scaffold is removed by degradation extraction,where the extraction removes, e.g., at least 75% of the porogenscaffold, at least 80% of the porogen scaffold, at least 85% of theporogen scaffold, at least 90% of the porogen scaffold, or at least 95%of the porogen scaffold. In aspects of this embodiment, a porogenscaffold is removed by degradation extraction, where the extractionremoves, e.g., about 75% to about 90% of the porogen scaffold, about 75%to about 95% of the porogen scaffold, about 75% to about 100% of theporogen scaffold, about 80% to about 90% of the porogen scaffold, about80% to about 95% of the porogen scaffold, about 80% to about 100% of theporogen scaffold, about 85% to about 90% of the porogen scaffold, about85% to about 95% of the porogen scaffold, or about 85% to about 100% ofthe porogen scaffold.

In still another embodiment, a porogen scaffold is removed by mechanicalextraction, where the extraction removes substantially all the porogenscaffold leaving a matrix defining an array of interconnected pores. Inaspects of this embodiment, a porogen scaffold is removed by mechanicalextraction, where the extraction removes, e.g., about 75% of the porogenscaffold, about 80% of the porogen scaffold, about 85% of the porogenscaffold, about 90% of the porogen scaffold, or about 95% of the porogenscaffold. In other aspects of this embodiment, a porogen scaffold isremoved by mechanical extraction, where the extraction removes, e.g., atleast 75% of the porogen scaffold, at least 80% of the porogen scaffold,at least 85% of the porogen scaffold, at least 90% of the porogenscaffold, or at least 95% of the porogen scaffold. In aspects of thisembodiment, a porogen scaffold is removed by mechanical extraction,where the extraction removes, e.g., about 75% to about 90% of theporogen scaffold, about 75% to about 95% of the porogen scaffold, about75% to about 100% of the porogen scaffold, about 80% to about 90% of theporogen scaffold, about 80% to about 95% of the porogen scaffold, about80% to about 100% of the porogen scaffold, about 85% to about 90% of theporogen scaffold, about 85% to about 95% of the porogen scaffold, orabout 85% to about 100% of the porogen scaffold.

The present specification discloses in part, biocompatible implantabledevice comprising a layer of porous material as disclosed herein,wherein the porous material covers a surface of the device. Abiocompatible implantable device is synonymous with “medical device”,“biomedical device”, “implantable medical device” or “implantablebiomedical device” and includes, without limitation, pacemakers, duramater substitutes, implantable cardiac defibrillators, tissue expanders,and tissue implants used for prosthetic, reconstructive, or aestheticpurposes, like breast implants, muscle implants or implants that reduceor prevent scarring. Examples of biocompatible implantable devices thatthe porous material disclosed herein can be attached to are describedin, e.g., Schuessler, Rotational Molding System for Medical Articles,U.S. Pat. No. 7,628,604; Smith, Mastopexy Stabilization Apparatus andMethod, U.S. Pat. No. 7,081,135; Knisley, Inflatable Prosthetic Device,U.S. Pat. No. 6,936,068; Falcon, Reinforced Radius Mammary Prosthesesand Soft Tissue Expanders, U.S. Pat. No. 6,605,116; Schuessler,Rotational Molding of Medical Articles, U.S. Pat. No. 6,602,452; Murphy,Seamless Breast Prosthesis, U.S. Pat. No. 6,074,421; Knowlton, SegmentalBreast Expander For Use in Breast Reconstruction, U.S. Pat. No.6,071,309; VanBeek, Mechanical Tissue Expander, U.S. Pat. No. 5,882,353;Hunter, Soft Tissue Implants and Anti-Scarring Agents, Schuessler,Self-Sealing Shell For Inflatable Prostheses, U.S. Patent Publication2010/0049317; U.S. 2009/0214652; Schraga, Medical Implant ContainingDetection Enhancing Agent and Method For Detecting Content Leakage, U.S.Patent Publication 2009/0157180; Schuessler, All-Barrier ElastomericGel-Filled Breast Prosthesis, U.S. Patent Publication 2009/0030515;Connell, Differential Tissue Expander Implant, U.S. Patent Publication2007/0233273; and Hunter, Medical implants and Anti-Scarring Agents,U.S. Patent Publication 2006/0147492; Van Epps, Soft Filled ProsthesisShell with Discrete Fixation Surfaces, International Patent PublicationWO/2010/019761; Schuessler, Self Sealing Shell for InflatableProsthesis, International Patent Publication WO/2010/022130; Yacoub,Prosthesis Implant Shell, International Application No. PCT/US09/61045,each of which is hereby incorporated by reference in its entirety.

A biocompatible implantable device disclosed herein can be implantedinto the soft tissue of an animal during the normal operation of thedevice. Such implantable devices may be completely implanted into thesoft tissue of an animal body (i.e., the entire device is implantedwithin the body), or the device may be partially implanted into ananimal body (i.e., only part of the device is implanted within an animalbody, the remainder of the device being located outside of the animalbody). A biocompatible implantable device disclosed herein can also beaffixed to soft tissue of an animal during the normal operation of themedical device. Such devices are typically affixed to the skin of ananimal body.

The present specification discloses, in part, a porous material thatcovers a surface of the biocompatible implantable device. Any of theporous materials disclosed herein can be used as the porous materialcovering a surface of a biocompatible implantable device. In general,the surface of a biocompatible implantable device is one exposed to thesurrounding tissue of an animal in a manner that promotes tissue growth,and/or reduces or prevents formation of fibrous capsules that can resultin capsular contracture or scarring.

Thus, in an embodiment, a porous material covers the entire surface of abiocompatible implantable device. In another embodiment, a porousmaterial covers a portion of a surface of a biocompatible implantabledevice. In aspects of this embodiment, a porous material covers to afront surface of a biocompatible implantable device or a back surface ofa biocompatible implantable device. In other aspects, a porous materialcovers only to, e.g., about 20%, about 30%, about 40%, about 50%, about60%, about 70%, about 80% or about 90% of the entire surface of abiocompatible implantable device, a front surface of a biocompatibleimplantable device, or a back surface of a biocompatible implantabledevice. In yet other aspects, a porous material is applied only to,e.g., at least 20%, at least 30%, at least 40%, at least 50%, at least60%, at least 70%, at least 80% or at least 90% of the entire surface ofa biocompatible implantable device, a front surface of a biocompatibleimplantable device, or a back surface of a biocompatible implantabledevice. In still other aspects, a porous material is applied only to,e.g., at most 20%, at most 30%, at most 40%, at most 50%, at most 60%,at most 70%, at most 80% or at most 90% of the entire surface of abiocompatible implantable device, a front surface of a biocompatibleimplantable device, or a back surface of a biocompatible implantabledevice. In further aspects, a porous material is applied only to, e.g.,about 20% to about 100%, about 30% to about 100%, about 40% to about100%, about 50% to about 100%, about 60% to about 100%, about 70% toabout 100%, about 80% to about 100%, or about 90% to about 100% of theentire surface of a biocompatible implantable device, a front surface ofa biocompatible implantable device, or a back surface of a biocompatibleimplantable device.

The layer of porous material covering a biocompatible implantable devicecan be of any thickness with the proviso that the material thicknessallows tissue growth within the array of interconnected of pores of amatrix in a manner sufficient to reduce or prevent formation of fibrouscapsules that can result in capsular contracture or scarring.

Thus, in an embodiment, a layer of porous material covering abiocompatible implantable device is of a thickness that allows tissuegrowth within the array of interconnected of pores of a matrix in amanner sufficient to reduce or prevent formation of fibrous capsulesthat can result in capsular contracture or scarring. In aspects of thisembodiment, a layer porous material covering a biocompatible implantabledevice comprises a thickness of, e.g., about 100 μm, about 200 μm, about300 μm, about 400 μm, about 500 μm, about 600 μm, about 700 μm, about800 μm, about 900 μm, about 1 mm, about 2 mm, about 3 mm, about 4 mm,about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, or about 10mm. In other aspects of this embodiment, a layer porous materialcovering a biocompatible implantable device comprises a thickness of,e.g., at least 100 μm, at least 200 μm, at least 300 μm, at least 400μm, at least 500 μm, at least 600 μm, at least 700 μm, at least 800 μm,at least 900 μm, at least 1 mm, at least 2 mm, at least 3 mm, at least 4mm, at least 5 mm, at least 6 mm, at least 7 mm, at least 8 mm, at least9 mm, or at least 10 mm. In yet other aspects of this embodiment, alayer porous material covering a biocompatible implantable devicecomprises a thickness of, e.g., at most 100 μm, at most 200 μm, at most300 μm, at most 400 μm, at most 500 μm, at most 600 μm, at most 700 μm,at most 800 μm, at most 900 μm, at most 1 mm, at most 2 mm, at most 3mm, at most 4 mm, at most 5 mm, at most 6 mm, at most 7 mm, at most 8mm, at most 9 mm, or at most 10 mm. In still other aspects of thisembodiment, a layer porous material covering a biocompatible implantabledevice comprises a thickness of, e.g., about 100 μm to about 500 μm,about 100 μm to about 1 mm, about 100 μm to about 5 mm, about 500 μm toabout 1 mm, about 500 μm to about 2 mm, about 500 μm to about 3 mm,about 500 μm to about 4 mm, about 500 μm to about 5 mm, about 1 mm toabout 2 mm, about 1 mm to about 3 mm, about 1 mm to about 4 mm, about 1mm to about 5 mm, or about 1.5 mm to about 3.5 mm.

The present specification discloses in part, a method for makingbiocompatible implantable device comprising a porous material. In anaspect, a method for making biocompatible implantable device comprisesthe step of attaching a porous material to the surface of abiocompatible implantable device. In another aspect, a method for makingbiocompatible implantable device comprises the steps of a) preparing asurface of a biocompatible implantable device to receive porousmaterial, b) attaching a porous material to the prepared surface of thedevice. Any of the porous materials disclosed herein can be used as theporous material attached to a surface of a biocompatible implantabledevice.

In yet another aspect, a method for making biocompatible implantabledevice comprising the step of: a) coating a mandrel with a matrixmaterial base; b) curing the matrix material base to form a base layer;c) coating the cured base layer with a matrix material base; d) coatingthe matrix material base with porogens to form a matrix material-coatedporogen mixture; e) treating the matrix material-coated porogen mixtureto form a porogen scaffold comprising fused porogens and cure the matrixmaterial; and f) removing the porogen scaffold, wherein porogen scaffoldremoval results in a porous material, the porous material comprising amatrix defining an array of interconnected pores. In this method steps(c) and (d) can be repeated multiple times until the desired thicknessof the material layer is achieved.

The present specification discloses, in part, preparing a surface of abiocompatible implantable device to receive porous material. Preparing asurface of a biocompatible implantable device to receive porous materialcan be accomplished by any technique that does not destroy the desiredproperties of the porous material or the biocompatible implantabledevice. As a non-limiting example, a surface of a biocompatibleimplantable device can be prepared by applying a bonding substance.Non-limiting examples of bonding substances include silicone adhesives,such as, e.g., RTV silicone and HTV silicone. The bonding substance isapplied to the surface of a biocompatible implantable device, the porousmaterial, or both, using any method known in the art, such as, e.g.,cast coating, spray coating, dip coating, curtain coating, knifecoating, brush coating, vapor deposition coating, and the like.

The present specification discloses, in part, attaching a porousmaterial to a surface of a biocompatible implantable device. The porousmaterial can be attached to the entire surface of the device, or only toportions of the surface of the device. As a non-limiting example, porousmaterial is attached only to the front surface of the device or only theback surface of the device. Attachment of a porous material to a surfaceof a biocompatible implantable device can be accomplished by anytechnique that does not destroy the desired properties of the porousmaterial or the biocompatible implantable device.

For example, attachment can occur by adhering an already formed porousmaterial onto a surface of a biocompatible implantable device usingmethods known in the art, such as, e.g., gluing, bonding, melting. Forinstance, a dispersion of silicone is applied as an adhesive onto asurface of a biocompatible implantable device, a porous material sheet,or both, and then the two materials are placed together in a manner thatallows the adhesive to attached the porous material to the surface ofthe device in such a way that there are no wrinkles on the surface ofthe device. The silicone adhesive is allowed to cure and then the excessmaterial is cut off creating a uniform seam around the device. Thisprocess results in a biocompatible implantable device comprising aporous material disclosed herein. Examples 2 and 4 illustrate method ofthis type of attachment.

Alternatively, attachment can occur by forming the porous materialdirectly onto a surface of a biocompatible implantable device usingmethods known in the art, such as, e.g., cast coating, spray coating,dip coating, curtain coating, knife coating, brush coating, vapordeposition coating, and the like. For instance, a matrix material baseis applied to a mandrel and cured to form a base layer of cured matrixmaterial. The base layer is then initially coated with a matrix materialbase and then subsequently with porogens to create a matrixmaterial-coated porogen mixture. This mixture is then treated asdisclosed herein to form a porogen scaffold and cure the matrixmaterial. The porogen scaffold is then removed, leaving a layer ofporous material on the surface of the device. The thickness of theporous material layer can be increased by repeated coatings ofadditional matrix material base and porogens. Examples 5-8 illustratemethod of this type of attachment.

Regardless of the method of attachment, the porous material can beapplied to the entire surface of a biocompatible implantable device, oronly to portions of the surface of a biocompatible implantable device.As a non-limiting example, porous material is applied only to the frontsurface of a biocompatible implantable device or only the back surfaceof a biocompatible implantable device.

Thus, in an embodiment, a porous material is attached to a surface of abiocompatible implantable device by bonding a porous material to asurface of a biocompatible implantable device. In aspects of thisembodiment, a porous material is attached to a surface of abiocompatible implantable device by gluing, bonding, or melting theporous material to a surface of a biocompatible implantable device.

In another embodiment, a porous material is attached to a surface of abiocompatible implantable device by forming the porous material onto asurface of a biocompatible implantable device. In aspects of thisembodiment, a porous material is attached to a surface of abiocompatible implantable device by cast coating, spray coating, dipcoating, curtain coating, knife coating, brush coating, or vapordeposition coating.

In another aspect of this embodiment, forming a porous material on asurface of a biocompatible implantable device comprises coating a curedmatrix material base layer with a matrix material base and then coatingthe uncured matrix material base with porogens to form a matrixmaterial-coated porogen mixture. In other aspects of this embodiment,coating a cured matrix material base layer with an uncured matrixmaterial base and then coating the uncured matrix material base withporogens to form a matrix material-coated porogen mixture can berepeated, e.g., at least once, at least twice, at least three times, atleast four times, at least five times, at least six times, at leastseven times, at least eight times, at least nine times, or at least tentimes, before the mixture is treated.

In another embodiment, a porous material is applied to the entiresurface of a biocompatible implantable device. In another embodiment, aporous material is applied to a portion of a surface of a biocompatibleimplantable device. In aspects of this embodiment, a porous material isapplied to a front surface of a biocompatible implantable device or aback surface of a biocompatible implantable device. In other aspects, aporous material is applied only to, e.g., about 20%, about 30%, about40%, about 50%, about 60%, about 70%, about 80% or about 90% of theentire surface of a biocompatible implantable device, a front surface ofa biocompatible implantable device, or a back surface of a biocompatibleimplantable device. In yet other aspects, a porous material is appliedonly to, e.g., at least 20%, at least 30%, at least 40%, at least 50%,at least 60%, at least 70%, at least 80% or at least 90% of the entiresurface of a biocompatible implantable device, a front surface of abiocompatible implantable device, or a back surface of a biocompatibleimplantable device. In still other aspects, a porous material is appliedonly to, e.g., at most 20%, at most 30%, at most 40%, at most 50%, atmost 60%, at most 70%, at most 80% or at most 90% of the entire surfaceof a biocompatible implantable device, a front surface of abiocompatible implantable device, or a back surface of a biocompatibleimplantable device. In further aspects, a porous material is appliedonly to, e.g., about 20% to about 100%, about 30% to about 100%, about40% to about 100%, about 50% to about 100%, about 60% to about 100%,about 70% to about 100%, about 80% to about 100%, or about 90% to about100% of the entire surface of a biocompatible implantable device, afront surface of a biocompatible implantable device, or a back surfaceof a biocompatible implantable device.

The layer of porous material applied to a biocompatible implantabledevice can be of any thickness with the proviso that the materialthickness allows tissue growth within the array of interconnected ofpores of a matrix in a manner sufficient to reduce or prevent formationof fibrous capsules that can result in capsular contracture or scarring.

Thus, in an embodiment, a layer of porous material applied to abiocompatible implantable device is of a thickness that allows tissuegrowth within the array of interconnected of pores of a matrix in amanner sufficient to reduce or prevent formation of fibrous capsulesthat can result in capsular contracture or scarring. In aspects of thisembodiment, a layer porous material applied to a biocompatibleimplantable device comprises a thickness of, e.g., about 100 μm, about200 μm, about 300 μm, about 400 μm, about 500 μm, about 600 μm, about700 μm, about 800 μm, about 900 μm, about 1 mm, about 2 mm, about 3 mm,about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm,or about 10 mm. In other aspects of this embodiment, a layer porousmaterial applied to a biocompatible implantable device comprises athickness of, e.g., at least 100 μm, at least 200 μm, at least 300 μm,at least 400 μm, at least 500 μm, at least 600 μm, at least 700 μm, atleast 800 μm, at least 900 μm, at least 1 mm, at least 2 mm, at least 3mm, at least 4 mm, at least 5 mm, at least 6 mm, at least 7 mm, at least8 mm, at least 9 mm, or at least 10 mm. In yet other aspects of thisembodiment, a layer porous material applied to a biocompatibleimplantable device comprises a thickness of, e.g., at most 100 μm, atmost 200 μm, at most 300 μm, at most 400 μm, at most 500 μm, at most 600μm, at most 700 μm, at most 800 μm, at most 900 μm, at most 1 mm, atmost 2 mm, at most 3 mm, at most 4 mm, at most 5 mm, at most 6 mm, atmost 7 mm, at most 8 mm, at most 9 mm, or at most 10 mm. In still otheraspects of this embodiment, a layer porous material applied to abiocompatible implantable device comprises a thickness of, e.g., about100 μm to about 500 μm, about 100 μm to about 1 mm, about 100 μm toabout 5 mm, about 500 μm to about 1 mm, about 500 μm to about 2 mm,about 500 μm to about 3 mm, about 500 μm to about 4 mm, about 500 μm toabout 5 mm, about 1 mm to about 2 mm, about 1 mm to about 3 mm, about 1mm to about 4 mm, about 1 mm to about 5 mm, or about 1.5 mm to about 3.5mm.

EXAMPLES

The following examples illustrate representative embodiments nowcontemplated, but should not be construed to limit the disclosed porousmaterials, methods of forming such porous materials, biocompatibleimplantable devices comprising such porous materials, and methods ofmaking such biocompatible implantable devices.

Example 1 A Method of Making a Porous Material Sheet

This example illustrates how to make a sheet of porous materialcomprising a silicone-based elastomer as disclosed herein.

To coat porogens with an elastomer base, an appropriate amount of PLGA(50/50) porogens (500 μm diameter) is mixed with an appropriate amountof 35% (w/w) silicone in xylene (MED 6400; NuSil Technology LLC,Carpinteria, Calif.). The mixture is filtered through a 43 μm sieve toremove the excess silicone and is poured into about 20 cm×20 cm squaremold coated with a non-stick surface.

To treat an elastomer coated porogen mixture to allow fusing of theporogens to form a porogen scaffold and curing of the non-degradablebiocompatible elastomer, the PLGA/silicone mixture is placed into anoven and is heated at a temperature of 75° C. for 45 min, and then 126°C. for 75 minutes. After curing, the sheet of cured elastomer coatedporogen scaffold is removed.

To remove a porogen scaffold from the cured elastomer, the curedelastomer/porogen scaffold is immersed in methylene chloride. After 30minutes, the methylene chloride is removed and fresh methylene chlorideis added. After 30 minutes, the methylene chloride is removed and theresulting 20 cm×20 cm×1.5 mm sheet of porous material is air dried atambient temperature. This process results in a porous material sheet asdisclosed herein.

A sample from the sheet of porous material can be characterized bymicroCT analysis and/or scanning electron microscopy (SEM).

Porous materials of a similar characteristic are also produced using PCLporogens instead of PLGA porogens. Similarly, porogen diameters fromabout 50 μm to about 3000 μm can be used.

Example 2 A Method of Making a Biocompatible Implantable DeviceComprising a Porous Material

This example illustrates how to make a biocompatible implantable devicecomprising a porous material as disclosed herein.

Sheets of porous material comprising a matrix defining an interconnectedarray of pores is obtained as described in Example 1.

To attach a porous material to a biocompatible implantable device, afirst porous material sheet is coated with a thin layer of silicone andthen placed in the bottom cavity of a mold, adhesive side up. Abiocompatible implantable device is then placed on top of the materialsurface coated with the adhesive. A second porous material sheet is thencoated with a thin layer of silicone and applied to the uncoveredsurface of the biocompatible implantable device. The top piece of themold cavity is then fixed in place pressing the two material sheetstogether creating a uniform interface. The silicone adhesive is allowedto cure by placing the covered device into an oven and heated at atemperature of 126° C. for 75 minutes. After curing, excess material istrimmed off creating a uniform seam around the biocompatible implantabledevice. This process results in a biocompatible implantable devicecomprising a porous material as disclosed herein. See, e.g., FIG. 2.

Alternatively, the porous material can be laminated onto a biocompatibleimplantable device while the device is still on a mandrel. In thisprocess, a first porous material sheet is coated with a thin layer ofsilicone and then draped over the device on the mandrel in such a waythat there are no wrinkles on the surface. After curing the siliconeadhesive, as described above, another coating of silicone is applied tothe uncovered surface of the biocompatible implantable device and asecond porous material is stretched up to cover the back of the device.After curing the silicone adhesive, as described above, thebiocompatible implantable device is then taken off the mandrel and theexcess porous material is trimmed to create a uniform seam around thedevice. This process results in a biocompatible implantable devicecomprising a porous material as disclosed herein. See, e.g., FIG. 2.

Example 3 A Method of Making a Porous Material Shell

This example illustrates how to make a shell including a porous materialcomprising a silicone-based elastomer as disclosed herein.

To coat porogens with a non-degradable biocompatible elastomer, anappropriate amount of PLGA (50/50) porogens (500 μm diameter) is mixedwith an appropriate amount of 35% (w/w) silicone in xylene (MED 6400;NuSil Technology LLC, Carpinteria, Calif.). The mixture is filteredthrough a 43 μm sieve to remove the excess silicone.

The filtered elastomer coated porogen mixture is poured into a mold inthe shape of a breast implant shell and the mold is mechanicallyagitated to pack firmly the mixture. The thickness of the shell iscontrolled based upon the design of the shell mold.

To treat a matrix material-coated porogen mixture to allow fusing of theporogens to form a porogen scaffold and curing of the non-degradablebiocompatible elastomer, the PLGA/silicone mixture is placed into anoven and is heated at a temperature of 75° C. for 45 min, and then 126°C. for 75 minutes. After curing, the shell mold is dismantled and thecured elastomer coated porogen scaffold is removed.

To remove a porogen scaffold from the cured elastomer, the curedelastomer/porogen scaffold is immersed in methylene chloride. After 30minutes, the methylene chloride is removed and fresh methylene chlorideis added. After 30 minutes, the methylene chloride is removed and theresulting 30 cm×30 cm×1.5 mm sheet of porous material is air dried at anambient temperature of about 18° C. to about 22° C. This process resultsin a porous material shell as disclosed herein. See, e.g., FIG. 3.

A sample from the sheet of porous material can be characterized bymicroCT analysis and/or scanning electron microscopy (SEM).

Porous materials of a similar characteristic are also produced using PCLporogens instead of PLGA porogens. Similarly, porogen diameters fromabout 50 μm to about 3000 μm can be used.

Example 4 A Method of Making a Medical Device Including a PorousMaterial Surface

This example illustrates how to make a medical device including a porousmaterial surface disclosed herein.

A porous material shell comprising a matrix defining an interconnectedarray of pores is obtained as described in Example 3.

To attach the porous material shell to a medical device, for example, animplantable article such as a pacemaker or artificial valve, the surfaceof the device is coated with a thin layer of silicone. The materialshell is then placed over the adhesive coated device in a manner thatensures no wrinkles in the material form. The silicone adhesive is cureby placing the covered device into an oven and heating at a temperatureof 126° C. for 75 minutes. After curing, excess material is trimmed offcreating a uniform seam around the device. This process results in animplantable medical device comprising a porous material surface asdisclosed herein.

Example 5 A Method of Making an Implant Comprising a Porous Material

This example illustrates how to make an implant comprising a porousmaterial disclosed herein of about 0.5 mm to about 1.5 mm in thickness.

To prepare the surface of a device to receive a porous material, a baselayer of 35% (w/w) silicone in xylene (MED4810; NuSil Technology LLC,Carpinteria, Calif.) was coated on a mandrel (LR-10), placed into anoven, and cured at a temperature of 126° C. for 75 minutes.

To coat the base layer with a mixture comprising a non-degradablebiocompatible elastomer and porogens, the cured base layer was dippedfirst in 35% (w/w) silicone in xylene (MED4810; NuSil Technology LLC,Carpinteria, Calif.) and then air dried for about 3 minutes to allow thexylene to evaporate. After xylene evaporation, the Mandrel with theuncured silicone was dipped in PLGA porogens until the maximum amount ofporogens were absorbed into the uncured silicone. The mandrel with theuncured silicone/PLGA coating was air dried for about 60 minutes toallow the xylene to evaporate.

To treat an elastomer coated porogen mixture to allow fusing of theporogens to form a porogen scaffold and curing of the non-degradablebiocompatible elastomer, the Mandrel coated with the uncuredsilicone/PLGA mixture was placed into an oven and cured at a temperatureof 75° C. for 30 min, and then 126° C. for 75 minutes.

To remove porogen scaffold, the cured silicone/PLGA mixture was immersedin methylene chloride. After 30 minutes, the methylene chloride wasremoved and fresh methylene chloride was added. After 30 minutes, themethylene chloride was again removed and fresh methylene chloride wasadded. After 30 minutes, the methylene chloride was removed and theresulting implant comprising a porous material of about 0.5 mm to about1.5 mm was air dried at an ambient temperature of about 18° C. to about22° C. This process results in a biocompatible implantable devicecomprising a porous material as disclosed herein. See, e.g., FIG. 2 andFIG. 4.

A sample from the implant was characterized by SEM. This analysisrevealed that the porous material was about 1.4 mm to about 1.6 mm inthickness.

Porous materials of a similar characteristic are also produced using PCLporogens instead of PLGA porogens. Similarly, porogen diameters fromabout 50 μm to about 3000 μm can be used.

To increase the thickness of the porous material covering the baselayer, multiple dippings were performed to produce a mandrel coated withmultiple layers of an uncured silicone/porogen mixture. Dippings wererepeated until the desired thickness is achieved. Examples 4-6 belowdescribe specific examples of this multiple dipping technique.

Example 6 A Method of Making an Implant Comprising a Porous Material

This example illustrates how to make an implant comprising a porousmaterial disclosed herein of about 1 mm to about 2.5 mm in thickness.

A mandrel comprising a base layer of elastomer was prepared as describedin Example 3.

To coat the base layer with a mixture comprising a non-degradablebiocompatible elastomer and porogens, the cured base layer was dippedfirst in 35% (w/w) silicone in xylene (MED4810; NuSil Technology LLC,Carpinteria, Calif.) and then air dried for about 3 minutes to allow thexylene to evaporate. After xylene evaporation, the mandrel with theuncured silicone was dipped in PLGA porogens until the maximum amount ofporogens were absorbed into the uncured silicone. The mandrel with theuncured silicone/PLGA coating was air dried for about 60 minutes toallow the xylene to evaporate. After xylene evaporation, the mandrelcoated with the uncured silicone/PLGA porogen mixture was dipped firstin 35% (w/w) silicone in xylene, air dried to allow xylene evaporation(about 3 minutes), and then dipped in PLGA porogens until the maximumamount of porogens were absorbed into the uncured silicone. The mandrelwith the second coating of uncured silicone/PLGA porogen mixture was airdried for about 60 minutes to allow the xylene to evaporate.

The mandrel comprising the two coats of uncured silicone/PLGA porogenmixture was treated as described in Example 3.

To remove porogen scaffold, the cured silicone/PLGA mixture was immersedin methylene chloride. After 30 minutes, the methylene chloride wasremoved and fresh methylene chloride was added. After 30 minutes, themethylene chloride was again removed and fresh methylene chloride wasadded. After 30 minutes, the methylene chloride was removed and theresulting implant comprising a porous material of about 1 mm to about2.5 mm was air dried at an ambient temperature of about 18° C. to about22° C. This process results in a biocompatible implantable devicecomprising a porous material as disclosed herein. See, e.g., FIG. 2 andFIG. 4.

A sample from the implant was characterized by SEM and microCT analysis.This analysis revealed that the porous material was about 2 mm to about2.5 mm in thickness with a porosity of about 88%.

Porous materials of a similar characteristic are also produced using PCLporogens instead of PLGA porogens. Similarly, porogen diameters fromabout 50 μm to about 3000 μm can be used.

Example 7 A Method of Making an Implant Comprising a Porous Material

This example illustrates how to make an implant comprising a porousmaterial disclosed herein of about 2.5 mm to about 4.5 mm in thickness.

A mandrel comprising a base layer of elastomer was prepared as describedin Example 3.

To coat the base layer with a mixture comprising a non-degradablebiocompatible elastomer and porogens, the cured base layer was dippedfirst in 35% (w/w) silicone in xylene (MED4810; NuSil Technology LLC,Carpinteria, Calif.) and then air dried for about 3 minutes to allow thexylene to evaporate. After xylene evaporation, the mandrel with theuncured silicone was dipped in PLGA porogens until the maximum amount ofporogens were absorbed into the uncured silicone. The mandrel with theuncured silicone/PLGA coating was air dried for about 60 minutes toallow the xylene to evaporate. After xylene evaporation, the mandrelcoated with the uncured silicone/PLGA porogen mixture was dipped firstin 35% (w/w) silicone in xylene, air dried to allow xylene evaporation(about 3 minutes), and then dipped in PLGA porogens until the maximumamount of porogens were absorbed into the uncured silicone. The mandrelwith the second coating of uncured silicone/PLGA was air dried for about60 minutes to allow the xylene to evaporate. After xylene evaporation,the mandrel coated with the two layers of the uncured silicone/PLGAporogen mixture was dipped first in 32% (w/w) silicone in xylene, airdried to allow xylene evaporation (about 3 minutes), and then dipped inPLGA porogens until the maximum amount of porogens were absorbed intothe uncured silicone. The mandrel with the third coating of uncuredsilicone/PLGA porogen mixture was air dried for about 60 minutes toallow the xylene to evaporate.

The mandrel comprising the two coats of uncured silicone/PLGA porogenswas treated as described in Example 3.

To remove porogen scaffold, the cured silicone/PLGA mixture was immersedin methylene chloride. After 30 minutes, the methylene chloride wasremoved and fresh methylene chloride was added. After 30 minutes, themethylene chloride was again removed and fresh methylene chloride wasadded. After 30 minutes, the methylene chloride was removed and theresulting implant comprising a porous material of about 2.5 mm to about4.5 mm was air dried at an ambient temperature of about 18° C. to about22° C. This process results in a biocompatible implantable devicecomprising a porous material as disclosed herein. See, e.g., FIG. 2 andFIG. 4.

A sample from the implant was characterized by SEM and microCT analysis.This analysis revealed that the porous material was about 3.5 mm toabout 4.5 mm in thickness.

Porous materials of a similar characteristic are also produced using PCLporogens instead of PLGA porogens. Similarly, porogen diameters fromabout 50 μm to about 3000 μm can be used.

Example 8 A Method of Making an Implant Comprising a Porous Material

This example illustrates how to make an implant comprising a porousmaterial disclosed herein of about 3.5 mm to about 5.5 mm in thickness.

A mandrel comprising a base layer of elastomer was prepared as describedin Example 3.

To coat the base layer with a mixture comprising a non-degradablebiocompatible elastomer and porogens, the cured base layer was dippedfirst in 35% (w/w) silicone in xylene (MED4810; NuSil Technology LLC,Carpinteria, Calif.) and then air dried for about 3 minutes to allow thexylene to evaporate. After xylene evaporation, the Mandrel with theuncured silicone was dipped in PLGA porogens until the maximum amount ofporogens were absorbed into the uncured silicone. The mandrel with theuncured silicone/PLGA coating was air dried for about 60 minutes toallow the xylene to evaporate. After xylene evaporation, the mandrelcoated with the uncured silicone/PLGA porogen mixture was dipped firstin 35% (w/w) silicone in xylene, air dried to allow xylene evaporation(about 3 minutes), and then dipped in PLGA porogens until the maximumamount of porogens were absorbed into the uncured silicone. The mandrelwith the second coating of uncured silicone/PLGA was air dried for about60 minutes to allow the xylene to evaporate. After xylene evaporation,the mandrel coated with the two layers of the uncured silicone/PLGAporogen mixture was dipped first in 32% (w/w) silicone in xylene, airdried to allow xylene evaporation (about 3 minutes), and then dipped inPLGA porogens until the maximum amount of porogens were absorbed intothe uncured silicone. The mandrel with the third coating of uncuredsilicone/PLGA porogen mixture was air dried for about 60 minutes toallow the xylene to evaporate. After xylene evaporation, the mandrelcoated with the three layers of the uncured silicone/PLGA porogenmixture was dipped first in 28% (w/w) silicone in xylene, air dried toallow xylene evaporation (about 3 minutes), and then dipped in PLGAporogens until the maximum amount of porogens were absorbed into theuncured silicone. The mandrel with the fourth coating of uncuredsilicone/PLGA porogen mixture was air dried for about 60 minutes toallow the xylene to evaporate.

The mandrel comprising the two coats of uncured silicone/PLGA porogenswas treating as described in Example 3.

To remove porogen scaffold, the cured silicone/PLGA mixture was immersedin methylene chloride. After 30 minutes, the methylene chloride wasremoved and fresh methylene chloride was added. After 30 minutes, themethylene chloride was again removed and fresh methylene chloride wasadded. After 30 minutes, the methylene chloride was removed and theresulting implant comprising a porous material of about 3.5 mm to about5.5 mm was air dried at an ambient temperature of about 18° C. to about22° C. This process results in a biocompatible implantable devicecomprising a porous material as disclosed herein. See, e.g., FIG. 2 andFIG. 4.

A sample from the implant was characterized by microCT analysis. Thisanalysis revealed that the porous material was about 4.5 mm to about 5.5mm in thickness.

Porous materials of a similar characteristic are also produced using PCLporogens instead of PLGA porogens. Similarly, porogen diameters fromabout 50 μm to about 3000 μm can be used.

Example 9 A Method of Making a Porous Material Comprising a Carbon-BasedElastomer

This example illustrates how to make a porous material comprising arubber as disclosed herein.

To coat porogens with a carbon-based elastomer base, an appropriateamount of PMMA porogens (350 μm diameter) is mixed with an appropriateamount of a carbon-based elastomer base, such as, e.g., poly(isoprene),poly(butadiene), poly(isobutylene isoprene), poly(butadieneacrylonitrile), and poly(chloroprene). The mixture is filtered through a43 μm sieve to remove the excess rubber and is poured into about 20cm×20 cm square mold coated with a non-stick surface.

To treat a carbon-based elastomer base-coated porogen mixture to allowfusing of the porogens to form a porogen scaffold and curing of theelastomer, the rubber/PMMA mixture is placed into an oven and is heatedat a temperature of 70° C. to soften the rubber, sulfur and zinc oxideare added, and then this mixture is heated to 126° C. for 75 minutes.After curing, the sheet of cured elastomer coated porogen scaffold isremoved.

To remove a porogen scaffold from the cured carbon-based elastomer, thecured rubber/PMMA scaffold is immersed in acetone or chloroform. After30 minutes, the acetone or chloroform is removed and fresh acetone orchloroform is added. After 30 minutes, the acetone or chloroform isremoved and the resulting 20 cm×20 cm×1.5 mm sheet of porous material isair dried at ambient temperature. This process results in a porousmaterial sheet as disclosed herein.

A sample from the sheet of porous material can be characterized bymicroCT analysis and/or scanning electron microscopy (SEM). The porousmaterial may be further engineered for different applications.

Porous materials of a similar characteristic are also produced usingpolystyrene, PCL, PLGA or sugar porogens instead of PMMA porogens.Similarly, porogen diameters from about 50 μm to about 3000 μm can beused. Likewise, the porous material may be affixed to another componentin a manner similar to that described in Example 2. Similarly, theporous material may be shaped using a mold in a manner similar to thatdescribed in Example 3 and/or affixed to another component in a mannersimilar to that described in Example 4. Furthermore, the porous materialmay be part of a manufacturing process where it is integrated as acomponent in a manner similar to that described in Examples 5-8.

Example 10 A Method of Making a Porous Material Comprising aPoly(Vinyl)-Based Thermoplastic

This example illustrates how to make a porous material comprising athermoplastic as disclosed herein.

To coat porogens with an thermoplastic base, an appropriate amount ofsugar porogens (650 μm diameter) is mixed with an appropriate amount ofpoly(vinyl)-based thermoplastic, such as, e.g., poly(vinyl chloride),poly(vinylidene fluoride), poly(vinyl fluoride), poly(vinyl nitrate),and poly-(4-vinylphenol). The mixture is filtered through a 43 μm sieveto remove the excess poly(vinyl)-based thermoplastic and is poured intoabout 20 cm×20 cm square mold coated with a non-stick surface.

To treat a thermoplastic-coated porogen mixture to allow fusing of theporogens to form a porogen scaffold and hardening of the thermoplastic,the poly(vinyl)-based thermoplastic/sugar mixture is placed into an ovenand is heated at a temperature of 90° C. to soften the poly(vinyl)-basedthermoplastic, and then this mixture is heated to 120° C. for 30 minutesto fuse sugar porogens. The mixture is cooled to room temperature toallow hardening of the poly(vinyl)-based thermoplastic. After hardening,the sheet of hardened poly(vinyl)-based thermoplastic-coated porogenscaffold is removed.

To remove a porogen scaffold from the cured elastomer, the hardenedpoly(vinyl)-based thermoplastic/sugar scaffold is immersed in warmwater. After 30 minutes, the water is removed and fresh warm water isadded. After 30 minutes, the water is removed and the resulting 20 cm×20cm×1.5 mm sheet of porous material is air dried at ambient temperature.This process results in a porous material sheet as disclosed herein.

A sample from the sheet of porous material can be characterized bymicroCT analysis and/or scanning electron microscopy (SEM). The porousmaterial may be further engineered for different applications.

Porous materials of a similar characteristic are also produced usingpolystyrene, PCL, PLGA, PMMA, or polystyrene porogens instead of sugarporogens. Similarly, porogen diameters from about 50 μm to about 3000 μmcan be used. Likewise, the porous material may be affixed to anothercomponent in a manner similar to that described in Example 2. Similarly,the porous material may be shaped using a mold in a manner similar tothat described in Example 3 and/or affixed to another component in amanner similar to that described in Example 4. Furthermore, the porousmaterial may be part of a manufacturing process where it is integratedas a component in a manner similar to that described in Examples 5-8.

Example 11 A Method of Making a Porous Material Comprising ThermoplasticElastomer

This example illustrates how to make a porous material comprising athermoplastic elastomer as disclosed herein.

To coat porogens with an thermoplastic elastomer base, an appropriateamount of sugar porogens (250 μm diameter) is mixed with an appropriateamount of a thermoplastic elastomer, such as, e.g.,poly(styrene-co-butadiene-polystyrene) (SBS). The mixture is filteredthrough a 43 μm sieve to remove the excess SBS and is poured into about20 cm×20 cm square mold coated with a non-stick surface.

To treat a thermoplastic elastomer-coated porogen mixture to allowfusing of the porogens to form a porogen scaffold and curing of thethermoplastic elastomer, the SBS/sugar mixture is placed into an ovenand is heated at a temperature of 90° C. to soften the SBS, and thenthis mixture is heated to 120° C. for 30 minutes to fuse sugar porogens.After curing, the sheet of hardened SBS-coated porogen scaffold isremoved.

To remove a porogen scaffold from the cured elastomer, the hardenedpoly(vinyl)-based thermoplastic/sugar scaffold is immersed in warmwater. After 30 minutes, the water is removed and fresh warm water isadded. After 30 minutes, the water is removed and the resulting 20 cm×20cm×1.5 mm sheet of porous material is air dried at ambient temperature.This process results in a porous material sheet as disclosed herein.

A sample from the sheet of porous material can be characterized bymicroCT analysis and/or scanning electron microscopy (SEM). The porousmaterial may be further engineered for different applications.

Porous materials of a similar characteristic are also produced usingpolystyrene, PCL, PGLA, PMMA, or polystyrene porogens instead of sugarporogens. Similarly, porogen diameters from about 50 μm to about 3000 μmcan be used. Likewise, the porous material may be affixed to anothercomponent in a manner similar to that described in Example 2. Similarly,the porous material may be shaped using a mold in a manner similar tothat described in Example 3 and/or affixed to another component in amanner similar to that described in Example 4. Furthermore, the porousmaterial may be part of a manufacturing process where it is integratedas a component in a manner similar to that described in Examples 5-8.

Example 12 A Method of Making a Porous Material Comprising a ThermosetElastomer

This example illustrates how to make a porous material comprising athermoset elastomer as disclosed herein.

To coat porogens with an thermoset elastomer base, an appropriate amountof PMMA porogens (1,000 μm diameter) is mixed with an appropriate amountof a poly(urethane). The mixture is filtered through a 43 μm sieve toremove the excess poly(urethane) and is poured into about 20 cm×20 cmsquare mold coated with a non-stick surface.

To treat a thermoset elastomer-coated porogen mixture to allow fusing ofthe porogens to form a porogen scaffold and curing of the thermosetelastomer, the poly(urethane)/PMMA mixture is placed into an oven and isheated at a temperature of 126° C. for 75 minutes. After curing, thesheet of cured elastomer coated porogen scaffold is removed.

To remove a porogen scaffold from the cured elastomer, the curedpoly(urethane)/PMMA scaffold is immersed in acetone or chloroform. After30 minutes, the acetone or chloroform is removed and fresh acetone orchloroform is added. After 30 minutes, the acetone or chloroform isremoved and the resulting 20 cm×20 cm×1.5 mm sheet of porous material isair dried at ambient temperature. This process results in a porousmaterial sheet as disclosed herein.

A sample from the sheet of porous material can be characterized bymicroCT analysis and/or scanning electron microscopy (SEM). The porousmaterial may be further engineered for different applications.

Porous materials of a similar characteristic are also produced usingpolystyrene, PCL, PLGA, sugar, or polystyrene porogens instead of PMMAporogens. Similarly, porogen diameters from about 50 μm to about 3000 μmcan be used. Likewise, the porous material may be affixed to anothercomponent in a manner similar to that described in Example 2. Similarly,the porous material may be shaped using a mold in a manner similar tothat described in Example 3 and/or affixed to another component in amanner similar to that described in Example 4. Furthermore, the porousmaterial may be part of a manufacturing process where it is integratedas a component in a manner similar to that described in Examples 5-8.

It can be appreciated that porous materials are provided by the presentinvention can have numerous industrial, household and medical uses. Forexample, porous materials in the biomedical field are provided which canbe components of devices and articles useful for tissueengineering/regeneration, wound dressings, drug release matrices,membranes for separations and filtration, sterile filters, artificialkidneys, absorbents, hemostatic devices, and the like. In variousindustrial and household applications, porous materials are providedwhich can make up insulating materials, packaging materials, impactabsorbers, liquid or gas absorbents, and wound dressings. The materialprovided also can be used as components of personal hygiene products,such as but not limited to, cleaning and cleansing pads, wipes andswabs, deodorant, disposable towels, dry shampoo, facial tissues,handkerchiefs, hygiene wipes, paper towels, shaving brushes, tampons,towels, underarm liners, washing mitts, and wet wipes, membranes,filters and so forth. Many other uses are contemplated for the presentmaterials and are considered to be within the scope of the invention.

In closing, it is to be understood that although aspects of the presentspecification have been described with reference to the variousembodiments, one skilled in the art will readily appreciate that thespecific examples disclosed are only illustrative of the principles ofthe subject matter disclosed herein. Therefore, it should be understoodthat the disclosed subject matter is in no way limited to a particularmethodology, protocol, and/or reagent, etc., described herein. As such,various modifications or changes to or alternative configurations of thedisclosed subject matter can be made in accordance with the teachingsherein without departing from the spirit of the present specification.Lastly, the terminology used herein is for the purpose of describingparticular embodiments only, and is not intended to limit the scope ofthe present invention, which is defined solely by the claims.Accordingly, the present invention is not limited to that precisely asshown and described.

Certain embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention. Ofcourse, variations on these described embodiments will become apparentto those of ordinary skill in the art upon reading the foregoingdescription. The inventor expects skilled artisans to employ suchvariations as appropriate, and the inventors intend for the invention tobe practiced otherwise than specifically described herein. Accordingly,this invention includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.

Groupings of alternative elements or embodiments of the inventiondisclosed herein are not to be construed as limitations. Each groupmember may be referred to and claimed individually or in any combinationwith other members of the group or other elements found herein. It isanticipated that one or more members of a group may be included in, ordeleted from, a group for reasons of convenience and/or patentability.When any such inclusion or deletion occurs, the specification is deemedto contain the group as modified thus fulfilling the written descriptionof all Markush groups used in the appended claims.

Unless otherwise indicated, all numbers expressing quantities ofingredients, properties such as molecular weight, reaction conditions,and so forth used in the specification and claims are to be understoodas being modified in all instances by the term “about.” As used herein,the term “about” means that the item, parameter or term so qualifiedencompasses a range of plus or minus ten percent above and below thevalue of the stated item, parameter or term. Accordingly, unlessindicated to the contrary, the numerical parameters set forth in thespecification and attached claims are approximations that may varydepending upon the desired properties sought to be obtained by thepresent invention. At the very least, and not as an attempt to limit theapplication of the doctrine of equivalents to the scope of the claims,each numerical parameter should at least be construed in light of thenumber of reported significant digits and by applying ordinary roundingtechniques. Notwithstanding that the numerical ranges and parameterssetting forth the broad scope of the invention are approximations, thenumerical values set forth in the specific examples are reported asprecisely as possible. Any numerical value, however, inherently containscertain errors necessarily resulting from the standard deviation foundin their respective testing measurements.

The terms “a,” “an,” “the” and similar referents used in the context ofdescribing the invention (especially in the context of the followingclaims) are to be construed to cover both the singular and the plural,unless otherwise indicated herein or clearly contradicted by context.Recitation of ranges of values herein is merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the range. Unless otherwise indicated herein, eachindividual value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g., “such as”) provided herein isintended merely to better illuminate the invention and does not pose alimitation on the scope of the invention otherwise claimed. No languagein the specification should be construed as indicating any non-claimedelement essential to the practice of the invention.

Specific embodiments disclosed herein may be further limited in theclaims using consisting of or consisting essentially of language. Whenused in the claims, whether as filed or added per amendment, thetransition term “consisting of” excludes any element, step, oringredient not specified in the claims. The transition term “consistingessentially of” limits the scope of a claim to the specified materialsor steps and those that do not materially affect the basic and novelcharacteristic(s). Embodiments of the invention so claimed areinherently or expressly described and enabled herein.

All patents, patent publications, and other publications referenced andidentified in the present specification are individually and expresslyincorporated herein by reference in their entirety for the purpose ofdescribing and disclosing, for example, the methodologies described insuch publications that might be used in connection with the presentinvention. These publications are provided solely for their disclosureprior to the filing date of the present application. Nothing in thisregard should be construed as an admission that the inventors are notentitled to antedate such disclosure by virtue of prior invention or forany other reason. All statements as to the date or representation as tothe contents of these documents is based on the information available tothe applicants and does not constitute any admission as to thecorrectness of the dates or contents of these documents.

What is claimed is:
 1. A method for forming an elastic, porous structuresuitable for implantation in a mammal, the method comprising the stepsof: a) coating porogens with a matrix material to form a matrixmaterial-coated porogen mixture, wherein the matrix material is apoly(lactic-co-glycolic acid) (PLGA); b) filtering the matrixmaterial-coated porogen mixture through a sieve to remove excess matrixmaterial; c) pouring the filtered mixture into a mold; d) treating thefiltered mixture to form a scaffold comprising fused porogens and curedmatrix material, wherein the scaffold comprises a three-dimensionalstructure in the form of the mold; and e) removing the fused porogensfrom the scaffold, wherein fused porogen removal results in a porousmaterial comprising the cured matrix material defining an array ofinterconnected pores.
 2. The method of claim 1, wherein in the scaffoldcomprises a three-dimensional structure wherein the diameter ofsubstantially all the connections between each fused porogen in betweenabout 15% to about 80% of the mean porogen diameter.
 3. The method ofclaim 1, wherein the cured matrix material exhibits an elasticelongation of at least 80%.
 4. The method of claim 1, wherein the matrixmaterial is a silicone elastomer.
 5. The method of claim 1, wherein theporogens are porogens having a diameter of 50 μm to about 3000 μm. 6.The method of claim 1, wherein the porogens are porogens having adiameter of about 500 μm.
 7. The method of claim 1, wherein the porogensare porogens having a diameter of about 650 μm.
 8. A method for forminga tissue engineering scaffold suitable for implantation in a mammal, themethod comprising the steps of: a) coating porogens with a matrixmaterial to form a matrix material-coated porogen mixture, wherein theporogens are porogens having a diameter of 50 μm to about 3000 μm; b)filtering the matrix material-coated porogen mixture through a sieve toremove excess matrix material; c) pouring the filtered mixture into amold; d) treating the filtered mixture to form a scaffold comprisingfused porogens and cured matrix material, wherein the scaffold comprisesa three-dimensional structure in the form of the mold; and e) removingthe fused porogens from the scaffold, wherein fused porogen removalresults in a porous material comprising the cured matrix materialdefining an array of interconnected pores.
 9. The method of claim 8,wherein in the scaffold comprises a three-dimensional structure whereinthe diameter of substantially all the connections between each fusedporogen in between about 15% to about 80% of the mean porogen diameter.10. The method of claim 8, wherein the cured matrix material exhibits anelastic elongation of at least 80%.
 11. The method of claim 8, whereinthe matrix material is a silicone elastomer.
 12. The method of claim 8,wherein the matrix material is a poly(lactic-co-glycolic acid) (PLGA).13. The method of claim 8, wherein the porogens are porogens having adiameter of about 500 μm.
 14. The method of claim 8, wherein theporogens are porogens having a diameter of about 650 μm.
 15. A methodfor forming an elastic porous article for biomedical applications, themethod comprising the steps of: a) coating porogens with a matrixmaterial to form a matrix material-coated porogen mixture, wherein theporogens are porogens having a diameter of 50 μm to about 3000 μm; b)filtering the matrix material-coated porogen mixture through a sieve toremove excess matrix material; c) pouring the filtered mixture into amold; d) treating the filtered mixture to form a scaffold comprisingfused porogens and cured matrix material, wherein the scaffold comprisesa three-dimensional structure in the form of the mold; and e) removingthe fused porogens from the scaffold, wherein fused porogen removalresults in a porous material comprising the cured matrix materialdefining an array of interconnected pores.
 16. The method of claim 15,wherein the porous article is a membrane for filtration or separation.17. The method of claim 15, wherein the porous article is a wounddressing.
 18. The method of claim 15, wherein the porous article is adrug release matrix.